

I States 

nmental Protection 
V 


Office of Air 
and Radiation 
Washington DC 20460 


November 1986 



MLCM 93/01946 


FT MEADE 

GenCol1 



otor Vehicle Tampering 
survey — 1985 


















United States Environmental Protection Agency 
Office of Air and Radiation 


MOTOR VEHICLE TAMPERING SURVEY - 1985 


November 1986 


FIELD OPERATIONS AND SUPPORT DIVISION 
OFFICE OF MOBILE SOURCES 
Washington, D.C. 






























TABLE OF CONTENTS 


EXECUTIVE SUMMARY . 1 

Introduction . 1 

Conclusions . 3 

BACKGROUND . 9 

SURVEY METHODS . 12 

Site Descriptions . 14 

RESULTS . 20 

Vehicle Tampering . 20 

Site and Aggregate Totals . 20 

Tampering Trends 1978-1985 . 22 

Types of Tampering . 27 

Vehicle Characteristics and Tampering . 30 

Vehicle Type . 30 

Vehicle Age . 32 

Manufacturer . 40 

I/M Programs and Geographic Bias . 43 

Effect of I/M Programs on Tampering . 44 

Tampering Trends for Selected Sites . 49 

Effectiveness of ATP-Only - Houston . 55 

Correlation Between Tampering and Idle Emissions . 56 

Fuel Switching . 63 

Fuel Switching Indicators and Overlap . 63 

Fuel Switching Rates . 65 

Fuel Switching by Vehicle Type . 69 

Fuel Switching and Vehicle Age . 69 

Catalyst Tampering and Fuel Switching . 72 

Gasoline Lead Concentrations . 74 

APPENDICES 

A. Relevant Portions of Clean Air Act . 75 

B. Survey and Data Recording Procedures . 76 

C. Emission Cutpoints for I/M Areas . 90 







































LIST OF FIGURES 


1. Component specific tampering rates: 

1979-1985 surveys . 5 

2. Overall and catalyst tampering by vehicle model 

year - 1985 survey . 7 

3. Breakdown of surveyed vehicles by condition and 

extent of tampering . 21 

4. Cumulative tampering prevalence as a function of 

vehicle age for the 1978-1985 surveys . 36 

5. Cumulative catalyst tampering rates as a function 

of vehicle age for the 1978-1985 surveys . 37 

6. Comparison of catalyst and overall tampering rates 

with vehicle age as a function of survey year . 39 

7. Tampering rates by manufacturer - 1985 survey . 41 

8. Tampering prevalence by manufacturer for the 

1978-1985 surveys . 42 

9. Comparison of tampering found in three locations in 

the same geographic area - 1985 suvrey . 45 


10. Converter tampering as a function of vehicle age for 
vehicles covered by different programs - 1985 Survey .. 51 

11. Comparison of data from 1985 survey sites that had 

been surveyed previously (Figs. 11(a) thru (d)) .... 53-54 


12. Distribution of survey sample among tampering, fuel 

switching, and idle test categories . 58 

13. Overlap of tampering and carburetor misadjustment 
among conventionally carbureted vehicles - 1985 

survey . 60 

14. Overlap of fuel switching indicators among unleaded 

vehicles - 1985 survey . 66 

15. Overlap of catalyst tampering and fuel switching 

among catalyst-equipped vehicles - 1985 survey . 73 

16. Lead concentrations in fuel sampled from misfueled 

vehicles . 73 


• • 

_ n _ 
















LIST OF TABLES 


1. Tampering Prevalence by Vehicle Type for 

Critical Control Components . 7 

2. 1985 Tampering Survey Summary . 23 

3. Classification of Vehicle Condition by Survey 

Site . 24 

4. Trends in Vehicle Condition Classification . 25 

5. Comparison of 1985 Survey Sample to Actual 

Nationwide Vehicle Fleet . 25 

6. Prevalence of Tampering by Component and Survey 

Year . 28 

7. Component-Specific Tampering Rates (percent) by 

Survey Location - 1985 Survey . 29 

8. Prevalence of Arguable Tampering by Component 

and Survey Year . 31 

9. Tampering Prevalence (and Sample Size) by Model 

Year and Vehicle Age at Time of Survey . 33 

10. Percentage of Catalyst Removal (and Sample Size) 
among Catalyst-Equipped Vehicles by Model Year 

and Vehicle Age at Time of Survey . 34 

11. Tampering Prevalence in I/M and non-l/M Areas . 47 

12. Component-Specific Tampering by Inspection Program 

Type - 1985 Survey . 47 

13. Catalyst Tampering among Vehicles for each Model 

Year covered by a Particular Program Type . 50 

14. Comparison of Tampering Rates in Houston for 

Components and Model Years covered by Anti tampering 
Program . 57 

15. Idle Test Failure Rates (percent) by 

Pollutant and Vehicle Condition . 62 


-ni- 

















16. Mean Idle Emissions by Vehicle Condition . 62 

17. Fuel Switching Rates among Unleaded Vehicles by 

Site and Indicator - 1985 Survey . 67 

18. Fuel Switching Prevalence among Unleaded Vehicles 

in I/M and non-I/M Areas . 68 

19. Fuel Switching Rates among Unleaded Vehicles by 

Indicator and Survey Year . 68 

20. Combined Tampering and Fuel Switching 

Rates - 1985 Survey . 70 

21. Percentage of Fuel Switching (and Sample Size) 
among Unleaded Vehicles by Model Year and vehicle 

Age at Time of Survey . 71 


-lv- 








EXECUTIVE SUMMARY 


INTRODUCTION 


Under the direction of the Field Operations and Support 
Division (FOSD) of the Environmental Protection Agency (EPA), 
contract personnel from Colorado State University (CSU) 
conducted a survey of light-duty motor vehicle tampering in 
15 cities between April and September, 1985. The areas surveyed 
and the total number of vehicles inspected are listed below. 


Kansas City, MO 469 
Kansas City, KS 475 
Fresno, CA 466 
Charlotte, NC 430 
Raleigh, NC 501 
Louisville, KY 456 
Wilmington, DE 502 
Portland, ME 436 
Northern Virginia 380 
Long Island, NY 305 
Philadelphia, PA 446 
Cleveland, OH 383 
Baton Rouge, LA 438 
Houston, TX 450 
Albuquerque, NM 449 


TOTAL 


6,586 vehicles 


The objectives of this survey were: 

1. To make local measurements of the types and extent of 
tampering and fuel switching. 

2. To extend and update the knowledge gained from earlier 
surveys on: 

a. The rates of overall and component-specific 
tampering and fuel switching. 


b. The distribution of tampering by vehicle age, 
type, manufacturer, and other variables of 
interest. 

c. The relationship between tampering and vehicle 
idle emissions. 


-2- 


d. The effect of vehicle inspection and maintenance 
(I/M) programs and anti tampering programs (ATPs) 
on tampering and fuel switching. 

To achieve these objectives, the inspection teams 
visually examined emission control devices and measured the 
idle hydrocarbon (HC) and carbon monoxide (CO) emissions of 
each vehicle. To provide information on fuel switching, the 
inspectors sampled gasoline from the tanks of vehicles (for 
later laboratory lead analysis), tested for lead deposits in 
tailpipes using Plumbtesrao® test paper, and checked the 
integrity of the fuel filler inlet restrictors. Four cate¬ 
gories were used to summarize the condition of the inspected 
vehicles: 

1. Tampered - at least one control device removed or 
rendered inoperative 

2. Arguably Tampered - possible but not clear-cut 
tampering (i.e., may have resulted from malmaintenance) 

3. Malfunctioning 

* 4. Okay - all control devices present and apparently 

operating properly 

These brief but thorough inspections were performed with the 
consent of the vehicle owners in a variety of settings more 
fully detailed elsewhere in this report. 

While the data from a survey such as this seem to invite 
inferences regarding program effectivenes, trends, etc., this 
approach can easily lead to incorrect conclusions. The sample 
size is reasonably adequate for evaluating tampering prevalence 
in any particular site, but the sampling of sites is neither 


-3- 


large nor random. Simple comparisons of site tampering 
rates across control program categories, for example, can 
overlook a variety of confounding factors. These may include 
geographical variability, fleet age structure and vehicle 
mix, variations in program maturity, coverage, history, and 
management, and the interactions among these factors. Straight¬ 
forward experimental control of these variables, difficult 
to achieve under the best of circumstances, becomes impossible 
in a situation where site selection is driven by programmatic 
considerations unrelated to the experimental questions. 

CONCLUSIONS 

For consistency with past surveys, the surveyed vehicles 
were classified as follows: tampered - 20%; arguably tampered 
- 27%; malfunctioning - 1%; okay - 52% (overall survey averages). 
This gross classification, while useful for some comparisons, 
is less informative concerning the emissions impact of 
tampering than an examination of component-specific rates. 

The 20% overall tampering rate is less than the rates found 
in 1984 and 1983 but greater than the rates from the other 
large surveys of 1978, 1979, and 1982. The apparent decrease 
in tampering activity may be an artifact of site-to-site 
variations in geographic location, truck proportion, and 
other characteristics, as well as disproportionate selection 
of sites with I/M and ATP programs. This decline may have 
emerged in part because this survey's sample is composed of 


-6- 


the 1985 survey. The fuel switching rate weighted by program 
status was 11%. The pattern of overlap among the three misfuel- 
ing indicators is discussed in detail later in this report. 

While the emissions impact of fuel switching depends upon its 
duration and certain vehicle characteristics, emission increases 
of 475% for HC and 425% for CO can easily occur. 

Age of Vehicle 

The probability that a vehicle has been tampered with is 
clearly related to its age, as has been shown in previous 
surveys. This is evident in Figure 2, which shows the rates 
by model year for both overall tampering and catalyst removal. 
These age-specific rates are investigated more thoroughly later 
in this report. 

Vehicle Types 

The tampering rates for light-duty trucks were equal to 
or higher than for automobiles in every tampering category, as 
shown in Table 1. The difference in catalytic converter 
tampering is particularly striking—over twice as prevalent 
for light-duty trucks as for passenger cars (10% vs 4%). 

Overall tampering and fuel switching rates among trucks mirror 
the general decline from 1984 rates observed in the survey as 


a whole. 




- 7 - 


Tamparlng Rate (2) 

Ovarall 
Tampering 

—B— 

Catalyst 
Tampering 


1965 1984 1963 1962 1961 1980 1979 1978 1977 1976 1975 

Vehicle Modal Year 

Figure 2. Overall and catalyst tampering by 
vehicle model year - 1985 survey. 



TABLE 1 


Tampering Prevalence by Vehicle Type for 
Critical Control Components 


Component/System 

Catalytic Converter 

Filler Neck Restrictor 

Air Pump System 

PCV System 

Evaporative Control 
System 

EGR System 

OVERALL 


Tampering Rate (%) 
Trucks Cars Overall 

10 4 5 

10 7 7 

11 6 7 


8 


22 


19 


20 


Fuel Switching 


13 


8 


9 












- 8 - 


I/M Programs and Tampering 

While the tampering rates in non-I/M areas were clearly 
equal to or greater than those with control programs for every 
critical component, such comparisons across program categories 
should be made very carefully. The classification of sites 
into program categories is necessarily somewhat rough. 

Fresno, for instance, has a biennial I/M + ATP program that 
has not been in effect long enough for all of the affected 
vehicles to have been inspected for the first time. Because of 
restricted program coverage aimed at newer vehicles (those 
less likely to be tampered with because of warranty status and 
age) the impact of a newly implemented program may not be 
observable for several years. 

A simple comparison of rates by program status would 
mislead one to conclude that antitampering programs are of 
doubtful utility when added onto I/M tailpipe programs. A 
different picture emerges, however, when we look at a group of 
sites roughly matched by geographical location, but varying in 
program status: Raleigh, Louisville, and Charlotte. Raleigh 
(non-I/M) has the highest rates of the three for catalyst and 
inlet tampering and fuel switching, followed by Louisville 
(I/M-only). Charlotte, which shares the geographical background 
of the other two cities but has an antitampering program augmenting 
its I/M program, has the lowest tampering rates of the three 
for the components specified. The effects of control programs 
on tampering are discussed in greater detail elsewhere in this 
report. 



-9- 


BACKGROUND 

Motor vehicle emissions in urban areas account for nearly 
90% of the total carbon monoxide (CO) and airborne lead, over 
30% of the hydrocarbons (HC), and nearly 40% of the oxides of 
nitrogen (NO x ) emitted into the atmosphere. As a result, a major 
focus of the nation's efforts to achieve compliance with clean 
air standards has been the control of emissions from mobile 
sources. The first pollution control devices were installed on 
vehicles in 1962, and most light-duty vehicles manufactured 
since 1968 have been equipped with a variety of emission control 
devices to meet required emissions standards. 

The 1977 amendments to the Clean Air Act (sections 
203(a)(3)(A) and (B), found in Appendix A) make it illegal for 
automobile dealers, repair and service facilities, and fleet 
operators to disconnect or render inoperative emission control 
devices or elements of design. Regulations issued under section 
211(c) of the Act (40 CFR Part 80) prohibit retailers and 
wholesale purchaser-consumers from introducing or allowing the 
introduction of leaded gasoline into vehicles labeled "unleaded 
gasoline only". The EPA's Field Operations and Support Division 
(FOSD), formerly the Mobile Source Enforcement Division (MSED), 
is responsible for enforcing the tampering and misfueling 
provisions of the Act. 


- 10 - 


Before 1978, the EPA had data suggesting that tampering 
with emission control devices and misfueling of "unleaded only" 
vehicles with leaded gasoline was occurring. Variability in 
the inspection procedures, however, prevented an accurate 
assessment of the nature and extent of the tampering. As a 
result, the Agency began conducting nationwide tampering 
surveys of light-duty motor vehicles in 1978 to determine the 
rates and types of tampering and fuel switching. These surveys 
were conducted in 19781, 1979 1 2 3 , 19813, 1982 4 5 6 , 1983$, and 1984$, 
either by FOSD directly, by EPA's National Enforcement 
Investigations Center (NEIC) under the direction of FOSD, or by 
EPA contractors supervised by FOSD personnel. Consistent 
inspection procedures were used throughout these surveys to 
permit comparisons and identification of trends. 


1 Motor Vehicle Tampering Survey (1978), U.S, Environmental 
Protection Agency, Mobile Source Enforcement Division, 
November 1978. 

Motor Vehicle Tampering Survey (1979), U.S. Environmental 
Protection Agency, National Enforcement Investigations 
Center, May 1980, EPA-330/1-80-001. 

3 Motor Vehicle Tampering Survey - 1981, Chattanooga, Tennessee 
and Houston, Texas, U.S. Environmental Protection Agency, 
National Enforcement Investigations Center, March 1982, 

EPA-330/1-82-001. 

4 Motor Vehicle Tampering Survey - 1982, U.S. Environmental 
Protection Agency, National Enforcement Investigations 
Center, April 1983, EPA-330/1-83-001. 

5 Motor Vehicle Tampering Survey - 1983, U.S. Environmental 
Protection Agency, Field Operations and Support Division, 
August 1984, EPA-460/1-84-001. 

6 Motor Vehicle Tampering Survey - 1984, U.S. Environmental 
Protection Agency, Field Operations and Support Division, 
October 1985, EPA-460/1-85-001. 



- 11 - 


The uses for the tampering surveys have evolved since the 
first survey was conducted in 1978. Since 1983, the tampering 
survey results for some locations have been used to calculate 
credits for State Implementation Plans (SIPs), the measures 
taken by State and local governments to achieve ambient air 
quality standards by reducing mobile source emissions. Data 
from the surveys is also used in the default database for the 
Agency's mobile source computer model (M0BILE3) to estimate 
both the emissions loading impact and the reductions that may 
be achieved by various control programs. Sites for the surveys 
are chosen in light of the need for data on specific areas 
either currently operating or considering programs, as well as 
the continuing need to monitor the types and extent of tampering 
and fuel switching nationwide. 

The 1985 tampering survey was conducted for FOSD by the 
National Center for Vehicle Emissions Control and Safety, 
Colorado State University (CSU). The inspection procedures 
used were consistent with those of previous surveys, and are 
described in detail in the next section of this report. 


- 12 - 


SURVEY METHODS 

The 1985 tampering survey was conducted in 15 cities between 
April and September, 1985. A goal of inspecting at least 300 
vehicles in each location was established to ensure a statistically 
meaningful database; 6,586 total vehicles were actually inspected. 
The mix of vehicles inspected was assumed to be a self-weighting 
sample, and no attempt was made to approximate the national 
vehicle mix. 

Each inspection team consisted of at least four members: 
three CSU personnel, one or two EPA representatives, and fre¬ 
quently a State or local agency representative. The CSU personnel, 
assisted by the State or local person, performed the actual 
inspections, while the EPA representative(s) supervised the survey. 
Each vehicle inspection included the following: 

1 . basic vehicle identification data recorded (year, 
make, model) 

2 . all emission control systems checked 

3. idle HC and CO emissions measured 

4. fuel sample collected from unleaded-only vehicles for 
lead analysis 

5. tailpipe tested for lead deposits using Plumbtesmo®^ 
test paper 

6 . integrity of fuel inlet restrictor checked 

6 Plumbtesmo® is a registered trademark, and appears hereafter 
without the ®. It is manufactured by Machery-Nagel, Duren, W. 
Germany, and marketed by Gallard-Schlesinger Chemical Corp., 

Carle Place, New York. 



-13- 


The inspection and recording procedures are detailed in 
Appendix B. The survey database has been reviewed by CSU, 
EPA, and the major automobile manufacturers to ensure its 
accuracy• 

The tampering survey included only 1975 and newer 
light-duty cars and trucks fueled with gasoline. For the 
purposes of the tampering surveys, a vehicle is considered 
to be "unleaded" if a dash label, tank label, or filler 
inlet restrictor is observed at the time of the inspection. 

A vehicle's designation as "unleaded" or "leaded" may be 
changed upon subsequent review of the data. Fuel switching 
rates are thus calculated based only on the unleaded vehicles 
surveyed. Similarly, tampering rates for specific components 
are based only on the vehicles originally equipped with the 
component. 

The inspections were performed with the consent of the 
vehicle owners at either roadside pullovers or inspection 
stations. The survey was designed to minimize the refusal 
rate of potential survey participants. A high refusal rate 
increases the uncertainty in the data gathered, and indivi¬ 
duals who have tampered with or misfueled their vehicles are 
less likely to allow their vehicles to be surveyed. The 
overall refusal rate was relatively low (7%), but some 


-14- 


survey sites had high refusal rates (see below). The tampering 
and misfueling rates at these particular locations might be 
significantly higher than reported here. A brief description 
of each survey site follows. 

Kansas City, Missouri - non-I/M 

Dates: April 22 - 26, 1985 

Vehicles Surveyed: 469 

Fuel Samples: 384 

Refusal Rate: 9% 

The Kansas City Police Department and Missouri State 

Highway Patrol provided officers to stop potential survey 

participants, and the inspectors solicited permission to 

conduct the inspections. Locations for pullovers were changed 

daily. 

Kansas City, Kansas - non-I/M 

Dates: April 29 - May 3, 1985 

Vehicles Surveyed: 475 

Fuel Samples: 386 

Refusal Rate: 5% 

Roadside pullovers were conducted with the help of the 

local law enforcement officers of municipalities in the Kansas 

City area. Inspection locations were changed daily and 

included Kansas City (two days), Shawnee, Overland Park, and 

Olathe . 

Fresno, California - I/M + ATP 

Dates: May 20 - 24, 1985 

Vehicles Surveyed: 466 

Fuel Samples: 297 

Refusal Rate: 5% 





-15- 


The California Highway Patrol provided officers to assist 
with the roadside pullovers. The California Bureau of 
Automotive Repair conducted a survey of driver's perceptions 
about emission control concurrently with the tampering 
inspections. Survey locations were changed daily. Fresno has 
had a decentralized biennial I/M and antitampering program 
since November, 1984; consequently less than 30% of the vehicles 
in Fresno had been inspected at the time of the survey. 

Charlotte, North Carolina - I/M + ATP 

Dates; June 3-7, 1985 

Vehicles Surveyed: 430 

Fuel Samples: 324 

Refusal Rate: 12% 

Roadside pullovers were conducted with the assistance 

of the Charlotte Police Department. Survey locations were 

changed daily. Charlotte (Mecklenburg County) enacted an 

annual decentralized I/M + ATP in December, 1982 which covers 

the last twelve model years. 

Raleigh, North Carolina - non-I/M 

Dates: June 10 - 14, 1985 

Vehicles Surveyed: 501 

Fuel Samples: 399 

Refusal Rate: 7% 

The North Carolina Department of Motor Vehicles provided 

officers to assist with the roadside pullovers. The surveys 

were conducted at five locations in the Raleigh metropolitan 


area. 




- 16 - 


Louisville, Kentucky - I/M-only 


Dates : 

Vehicles Surveyed: 
Fuel Samples: 
Refusal Rate: 


June 18 - 21, 1985 


456 

415 


7% 


The Louisville survey was conducted at four centralized 
inspection stations in the metropolitan Louisville area. The 
inspection team set up and conducted the survey at the entrance 
to the inspection lane each day. The centralized annual I/M 
program in Louisville (Jefferson County) was enacted in 
January, 1984. 

Wilmington, Delaware - I/M-only 

Dates: June 24 - 28, 1985 

Vehicles Surveyed: 502 

Fuel Samples: 417 

Refusal Rate: 8% 

The Wilmington survey was conducted with the assistance 

of the Delaware State Police, New Castle County Police, and 

Wilmington Police Department. The roadside pullover locations 

were changed daily, and were all located in the metropolitan 

Wilmington area. Wilmington (New Castle County) enacted an 

annual centralized I/M program in January, 1983. 

Portland, Maine - non-I/M 

Dates: July 8-12, 1985 

Vehicles Surveyed: 436 

Fuel Samples: 376 

Refusal Rate: 6% 





-17- 


The Portland survey was conducted at four locations in 
Portland and one location in South Portland. The inspection 
team was assisted by the Maine State Police, City of Portland 
Police, and the South Portland Police. 

Northern Virginia - I/M + ATP 

Dates: July 15-19, 1985 

Vehicles Surveyed: 380 

Fuel Samples: 332 

Refusal Rate: 10% 

The Northern Virginia survey was conducted in the Virginia 
suburbs of Washington, D.C. The Virginia State Police assisted 
with the roadside pullovers. Northern Virginia's annual 
decentralized I/M + ATP was enacted in December, 1981, and 
covers the previous eight model years. 

Long Island, New York - I/M + ATP 

Dates: July 22 - 26, 1985 

Vehicles Surveyed: 305 

Fuel Samples: 256 

Refusal Rate: 12% 

The survey was conducted in three New York State 

counties surrounding New York City: Suffolk, Nassau (2 days), 

and Westchester. The last day of the survey (in Rockland 

County) was cancelled because of inclement weather conditions. 

The New York State Environmental Conservation Police, Long 

Island Park Police, New York State Police, and Nassau County 

Police assisted with the roadside pullovers. The greater New 

York metropolitan area has had an annual decentralized I/M + 

ATP since January, 1982. 




-18- 


Philadelphia, Pennsylvania - I/M-only 

Dates: August 5-9, 1985 

Vehicles Surveyed: 446 

Fuel Samples: 361 

Refusal Rate: 6% 

The Philadelphia survey was conducted in Philadelphia 
four days and in Cheltenham township one day. The Philadelphia 
Highway Patrol and Cheltenham Township Police assisted with 
the roadside pullover. The greater Philadelphia metropolitan 
area has had a decentralized annual I/M program since June, 

1984 . 


Cleveland, Ohio - non-I/M 


Dates: 

Vehicles Surveyed: 
Fuel Samples: 
Refusal Rate: 


August 12 - 16, 1985 
383 
343 
9% 


Roadside pullovers were conducted with the help of local 
law enforcement officers in the municipalities in the Cleveland 
area. Inspection locations changed daily and included Cleveland 
(two days), Parma Heights, Garfield Heights, and Westlake. 


Baton Rouge, Louisiana - non-I/M 


Dates: 

Vehicles Surveyed: 
Fuel Samples: 
Refusal Rate: 


August 19 - 23, 1985 
438 
405 
3% 





- 19 - 


The Louisiana State Police provided officers to assist 
with the roadside pullovers. Inspection locations changed 
daily, and included Baton Rouge, East Baton Rouge, West Baton 
Rouge, Erwinsville, and Denham Springs. Baton Rouge was a 
non-I/M area at the time of the survey, but implemented an 
ATP only in September, 1985. 

Houston, Texas - ATP-only 

Dates: August 26 - 30, 1985 

Vehicles Surveyed: 450 

Fuel Samples: 369 

Refusal Rate: 6% 

The Houston survey was conducted at four locations in 
Houston and one location in South Houston. The Texas Department 
of Public Safety supplied officers to assist with the roadside 
pullovers. An annual decentralized ATP-only program was 
implemented in Houston (Harris County) in July, 1984. 

Albuquerque, New Mexico - non-I/M 

Dates: September 9-13, 1985 

Vehicles Surveyed: 449 

Fuel Samples: 410 

Refusal Rate: 6% 

The Albuquerque survey was conducted with the assistance 
of the New Mexico State Police. Survey locations were changed 
daily, and included Albuquerque (3 days), North Valley, and 
South Valley. Albuquerque is currently a non-I/M area, but 
had an I/M program from January, 1983 to March, 1984. 




- 22 - 


The frequency distribution of tampering instances for 
those vehicles classified as "tampered" is also shown in 
Figure 3. Forty-two percent of the tampered vehicles had 
multiple components tampered, of which 11% had four or more 
instances of tampering. 

Tables 2 and 3 summarize the 1985 survey data by site. 
Table 2 is a general survey summary, while Table 3 shows 
the vehicle condition classification by site. As in the 
1984 survey, the overall tampering rates in 1985 vary 
considerably from site to site. This can be attributed to 
the variety of program configurations among the cities 
surveyed and to geographic differences. 

Table 2 also contains the refusal rate at each survey 
site. While the overall refusal rate for the survey was 
relatively low (7%), three survey sites had refusal rates 
equal to or exceeding 10%. The actual tampering rates at 
these sites were probably higher than is reported here, 
since individuals who tamper with or misfuel their vehicles 
are less likely to allow their vehicles to be surveyed. 

2. Tampering Trends 1978-1985 

Table 4 shows the overall rates found in each of the 
seven tampering surveys. The overall tampering rate 
declined to 20% from the 22% and 26% rates found in 1984 
and 1983, respectively. Such direct comparisons between 



-23- 


TABLE 2 

1985 Tampering Survey Summary 


Survey 

Number of 

Tampering 

Misfueling 

Survey 

Refusal 

Location 

Vehicles 

Rate (%) 

Rate (%) 

Type* 

Rate (% ) 

Kansas City, MO 

469 

21 

10 

R 

9 

Kansas City, KS 

475 

25 

12 

R 

5 

Fresno, CA 

466 

21 

9 

R 

5 

Charlotte, NC 

430 

19 

6 

R 

12 

Raleigh, NC 

501 

18 

14 

R 

7 

Louisville, KY 

456 

23 

10 

C 

7 

Wilmington, DE 

502 

14 

5 

R 

8 

Portland, ME 

436 

12 

5 

R 

6 

N. Virginia 

380 

15 

4 

R 

10 

Long Island, NY 

305 

20 

7 

R 

12 

Philadelphia, PA 

446 

13 

3 

R 

6 

Cleveland, OH 

383 

22 

8 

R 

9 

Baton Rouge, LA 

438 

32 

21 

R 

3 

Houston, TX 

450 

18 

7 

R 

6 

Albuquerque, NM 

449 

24 

11 

R 

6 

OVERALL 

6,586 

20 

9 

— 

7 


*r = roadside pullovers, C = centralized I/M stations, 








- 24 - 


TABLE 3 

Classification of Vehicle Condition by Survey Site 


Survey Site 

Tampered 

(%) 

Arguably 
Tampered(%) 

Malfunctioning 

(%) 

Okay 

(%) 

Kansas City, MO* 

21 

24 

1 

55 

Kansas City, KS 

25 

24 

1 

50 

Fresno, CA 

21 

31 

2 

46 

Charlotte, NC 

19 

25 

1 

56 

Raleigh, NC 

18 

21 

1 

60 

Louisville, KY 

23 

37 

1 

39 

Wilmington, DE 

14 

28 

2 

56 

Portland, ME 

12 

24 

2 

61 

N. Virginia 

15 

25 

1 

59 

Long Island, NY 

20 

21 

3 

56 

Philadelphia, PA 

13 

29 

0 

57 

Cleveland, OH 

22 

26 

2 

49 

Baton Rouge, LA 

32 

25 

1 

42 

Houston, TX 

18 

28 

0 

53 

Albuquerque, NM 

24 

27 

2 

47 

OVERALL 

20 

27 

1 

52 


*The rates do not total 100% for some sites because of rounding 







- 25 - 


TABLE 4 

Trends in Vehicle Condition Classification 


Survey 

Year 

Tampered 

(%> 

Arguably 

Tampered(%) 

Malfunctioning 

(%) 

Okay 

(%) 

1978 

19 

48 

,2 

31 

1979 

18 

47 

2 

33 

1981* 

14 

45 

3 

38 

1982 

17 

38 

1 

44 

1983 

26 

30 

3 

42 

1984 

22 

29 

4 

46 

1985 

20 

27 

1 

52 


^Because the 1981 survey involved only two sites and a very 
limited sample size, these results may exhibit more variance 
than the other larger surveys. 


TABLE 5 


Comparison of 1985 Survey Sample to Actual Nationwide 

Vehicle Fleet 


Program 

Type 

Percentage within 
Survey Sample (%) 

Approx. Percentage of 
Nationwide Fleet (%)** 

non-I/M 

48 

75 


I/M-only 

21 

13 


I/M + ATP 

24 

1 1 


ATP-only 

(Houston) 

7 

1 


** Based on 1986 
Regional and 

vehicle population 
State contacts. 

data gathered from 

EPA 











-26- 


survey years, however, are not entirely appropriate. The 
surveys, for example, covered different sites, and had 

* 

different age and car/truck distributions. More importantly, 
because of the 1985 survey's specific goals, it greatly 
overrepresents the percentage of the national vehicle fleet 
under local control programs (see Table 5). I/M and I/M + 

ATP areas comprised 45% of the survey sample, while only 
approximately 24% of the national vehicle fleet were under 
such programs. 

This discrepancy can be corrected to some degree by 
applying a weighting factor to the tampering rates found 
under each program type. The 1985 tampering rate weighted 
for program representation is 21%. The 1985 weighted tampering 
rate can be compared to the weighted rates from the 1984, 

1983, and 1982 surveys (26%, 28%, and 19%, respectively.) 
Applying weighting factors to the 1981 and earlier surveys 
would be difficult, since some surveys contained no I/M 
areas. For the sake of clarity, only the actual, unweighted 
rates found during the surveys will be reported. Useful 
comparisons, however, can still be made between program types 
within a given year (e.g., I/M vs. non-I/M) or between the 
same program type in different years (e.g., non-I/M in 1984 


and 1985) . 


- 27 - 


3. Types of Tampering 

The tampering rates for specific emission control 
components and systems for the various survey years are 
presented in Table 6. The component-specific tampering 
rates for the 1985 survey are presented by survey site in 
Table 7. The arguable tampering percentages by component 
for the 1978-1985 surveys are presented in Table 8. Only 
those vehicles originally equipped with a particular 
component are considered when computing the tampering or 
arguable tampering rate for that component. The heated 
air intake was the only component that could be classified 
as either tampered or arguably tampered, based on its 
condition in a surveyed vehicle (see Appendix B). 

Table 6 shows that tampering with some major components 
(e.g., filler inlet restrictor and catalytic converter) 
has decreased since the 1984 survey. Tampering with the 
PCV, aspirator, and evaporative systems has increased 
since the 1984 survey. Tampering in general remained higher 
than in the 1982 and earlier surveys. 

Table 7 shows the wide variation in tampering rates 
for any given component from site to site. Catalytic 
converter removal, for example, ranged from 2% in Fresno 
to 14% in Baton Rouge. This range is partly due to the 
effectiveness of I/M and antitampering programs and geo¬ 
graphic differences, as will be discussed later in this 
report. 



- 28 - 


TABLE 6 

Prevalence of Tampering by Component and Survey Year 


Survey Year 


Component/System 


1978 1979 1981* 1982 1983 1984 1985 


Catalytic Converter 1% 

Filler Neck 3 

Restrictor 


1 % 


4% 


4% 


7% 


7% 


10 


5% 


Air Pump System 
Air Pump Belt 
Air Pump/Valve 

Aspirator** 

PCV System 

Evaporative 
Control System 

EGR System 
EGR Control Valve 
EGR Sensor 


7 

6 

3 

*** 

3 

3 


13 

12 

5 


5 

4 

2 

2 

3 

2 


10 

5 

7 


4 

4 

4 

0 

2 

2 


5 

5 

5 


5 

5 

4 

1 

3 

2 


10 

7 

7 


7 

7 

3 

1 

5 

5 


13 

9 

12 


7 

7 

4 

1 

2 

3 


10 

7 

6 


7 

4 
6 

2 

5 

4 


7 

6 

4 


Heated Air Intake 1 

Vacuum Spark 11 

Retard 


1 


0 


0 


1 

1 


1 

5 


★ ** 


Idle Stop 
Solenoid 


0 


0 


* * ★ 


Oxygen Sensor 


* * * * * * * * * * * * 


0 


0 


0 


*The 1981 survey was of limited scope, covering only two 
sites and 399 vehicles. 

**Vehicles with aspirated air systems are not equipped with 
other listed air-injection components, nor do conventional 
systems include aspirators. 

***Component not checked during survey. 










Component-Specific Tampering Rates (percent) by Survey Location - 1985 Survey 


- 29 - 


P 

0 

& 

p 

o 

p 

c 

Q) 

§J 


8 

P 

c 

8 

§ 

•i-i 

0 

CO 



<u 

| i 

^ CO 

8 .( 5 ? 

<0 

6 


P 

CO 

fi? 


P 

CO 

§ 


a 


p 

CO 

£ 


p 

-§ 

0 -H 

C p 
CO 


£ 


u p 

•<H 0 

£ti 

r—I 0 
<0 > 
P c 

ss 


HinHOM»ro^ , Niooro(NMco'i l o 

CNCNCNi—li—l<Ni—If—If—l(Nr—ICNCOr—(CNJCN 




vOr-ir^oo , ^‘vD'^)^rLn^oir)oo , ^ , cr>'^>r' 


roinr^t^-cNvo^rcNrominr^r^tor'Ln 


VOH^ , n^ l O ,l 5'(NlOoOl^! s -0>OO c Nt s » 


ctioctilO'— loof^^'^^oor-r^uncT'r- 


i^'OCNrooo^rorrr-iLncNvc^LOLOiri 

t—4 r-H 


>i O 

0 «>H 

ES 


o <9 


>i >i ^ 
4J 4-> < 
•H *rH CJ 

<J u 


CJ 

z 


CO 

0 

CO 

C 

2 


CO 

0 

CO 

c 

s 


a> 
p 
*• p 

o 0 

C *-H 
CO p 
0 03 

£ 6 


>h Ci3 

* a 

w 

cj * - s 

Z 0 c 
i—i o *• 
'H p^ 

jC *h rp C 
Cn > C 0 

•rH (/) -H H 

0 -rH £ P 
*—( Z3 *—iP 

& ass, 


< 

S a 5 

*> 0 O *■ 

0 'O -H 0 >< 
•rH C ^ •* O 1 H 
c 0 Outo 5 

•hhh C Q ■* 

p> 0 0 0 a c 

W H T3 H o 
•rH 0 0 C P 
> P>"H >00 

c --h 0 p 5 

z 3 ^ cj <2 :§ 












- 30 - 


Table 8 shows that idle limiter caps/sealed plugs remain 
the item most frequently arguably tampered (42%). The arguable 
tampering with limiter caps and sealed plugs, however, has 
continued to decline from a high of 83% in 1981. This is 
probably due to the widespread use of sealed plugs instead of 
limiter caps in recent years to deter carburetor adjustments. 
The sealed plugs are much more difficult to remove than the 
plastic limiter caps were. Arguable tampering with the 
heated air intake doubled in 1985, and tank label removal 
also remained high. 

4. Vehicle Characteristics and Tampering 

The next section of this report investigates the impact 
on tampering of three vehicle characteristics: type (car 
or truck), age, and manufacturer. 

Vehicle Type . The tampering prevalence for light-duty 
trucks was higher than for automobiles, as was mentioned 
previously (Table 1). The tampering rate for each emissions 
component on trucks was equal to or greater than on passenger 
cars, continuing the pattern observed in previous surveys. 

The catalytic converter tampering rate for trucks was more 
than double that for automobiles (10% vs. 4%). The fuel 
switching rate for trucks (13%) was also considerably higher 
than for automobiles (8%). 




- 31 - 


TABLE 8 

Prevalence of Arguable Tampering by Component 

and Survey Year 


Survey 

Year 

Limiter Cap/ 
Sealed Plugs 

Fuel Tank 
Cap 

Tank 

Label 

Dash 

Label 

Heated A 
Intake 

1978 

65% 

0% 

5% 

1% 

9% 

1979 

62 

1 

4 

1 

8 

1981 

83 

1 

4 

0 

9 

1982 

54 

2 

4 

1 

6 

1983 

54 

3 

9 

1 

14 

1984 

49 

1 

12 

3 

8 

1985 

42 

1 

10 

2 

16 








- 30 - 


Table 8 shows that idle limiter caps/sealed plugs remain 
the item most frequently arguably tampered (42%). The arguable 
tampering with limiter caps and sealed plugs, however, has 
continued to decline from a high of 83% in 1981. This is 
probably due to the widespread use of sealed plugs instead of 
limiter caps in recent years to deter carburetor adjustments. 
The sealed plugs are much more difficult to remove than the 
plastic limiter caps were. Arguable tampering with the 
heated air intake doubled in 1985, and tank label removal 
also remained high. 

4. Vehicle Characteristics and Tampering 

The next section of this report investigates the impact 
on tampering of three vehicle characteristics: type (car 
or truck), age, and manufacturer. 

Vehicle Type . The tampering prevalence for light-duty 
trucks was higher than for automobiles, as was mentioned 
previously (Table 1). The tampering rate for each emissions 
component on trucks was equal to or greater than on passenger 
cars, continuing the pattern observed in previous surveys. 

The catalytic converter tampering rate for trucks was more 
than double that for automobiles (10% vs. 4%). The fuel 
switching rate for trucks (13%) was also considerably higher 
than for automobiles (8%). 




- 31 - 


TABLE 8 

Prevalence of Arguable Tampering by Component 

and Survey Year 


Survey 

Year 

Limiter Cap/ 
Sealed Plugs 

Fuel Tank 
Cap 

Tank 

Label 

Dash 

Label 

Heated Ai 
Intake 

1978 

65% 

0% 

5% 

1% 

9% 

1979 

62 

1 

4 

1 

8 

1981 

83 

1 

4 

0 

9 

1982 

54 

2 

4 

1 

6 

1983 

54 

3 

9 

1 

14 

1984 

49 

1 

12 

3 

8 

1985 

42 

1 

10 

2 

16 








- 32 - 


Vehicle Age . Table 9 relates vehicle age and model 
year with tampering prevalence for the 1978-1985 surveys. 
Catalytic converter removal rates are similarly related to 
vehicle age and model year in Table 10. The results from 
any given survey are entered diagonally in each table. 

The results in Tables 9 and 10 indicate that vehicle 
tampering increases directly with vehicle age. Examining 
Table 9 diagonally (by survey) shows a fairly linear increase 
in the tampering rate with vehicle age for each survey. In 
the 1985 survey, for example, the tampering rate increases 
from 2% for first year (1985) vehicles to 54% among the 1975 
model year vehicles surveyed. Table 10 shows a similar, 
though less pronounced, increase in catalyst removal. Examin¬ 
ing these tables in this manner has the advantage of comparing 
data collected during one survey in one set of locations, but 
ignores the possible effects of model year differences (i.e., 
technology) on tampering. 

Two additional ways of analyzing Tables 9 and 10 address 
the impact of model year on tampering rates. Analyzing the 
tables horizontally (holding the model year constant) provides 
a look at the tampering rates over time for the vehicles of 
a particular model year. This approach shows the same distinct 
increase in tampering with vehicle age for all model years 
since 1975. (The 1974 and 1973 data sets are too small to 



Tampering Percentage (and Sample Size) by Model Year and Vehicle Aje at Time of Survey 


- 33 - 


5 

c 

5 

0 

3 


<T\ 


m 



x: 

4J 

c 

••H 

z 



cn 

r- 


vo 

ON 


co 

rH 


>_^ 



<T> 

VO 







CN 

in 

-—.. 

in 

00 

CTi 


co 

00 

•*_^ 

V_.* 


00 

<T> 

in 


co 

m 


0) 

4-1 


0 

r-H 

o 

•rH 

jC 


4-1 

0 

<0 


5 

O 

•iH 

u 

5 

s 

> 

$ 

5 

X 

•rH 

W 


5 

4-4 

•H 

Eli 


CN 

00 

rH 

CO 

VO 

o 

r^ 

00 

in 

n* 

rH 

r —1 

^ _ - 

'•—■" 

>._ ✓ 


e'¬ 

r-H 

o 

e'¬ 

en 



en 




«s 

^—* 

"—*» 






co 

<Ti 

O 



rH 



r- 

in 

<Ti 

r —1 

CN 

m 



VO 

in 

r-i 

co 

CN 

CN 



'—r 

_- 

''—" 

•w* 

'—■- 

" 



r^- 


n* 

VO 

CN 

vo 



co 

en 

•n* 

CN 

CO 

CO 




_ 

___ 





en 

00 

VO 

v 

CN CO 


vo 

o 

cn 

r —1 

CN 

in 


in 

in 

CN 

co 

in 

CN CN 



**—" 

-—^ 

^—- 

v_ * 

>_*» ^ 


in 

00 

<n 

VO 

<T> 

r- cn 


CM 

CM 

cn 

CN 

CN 

cn cn 







^ __ s 

r- 

VO 

00 

o 

-—n 


i-i vo 

o 

i—i 

00 

cn 

VO 


("- r-> 

V£> 

in 

Csj 


VO 


CN CN 


V_^ 

"—" 


"— 1 - 



rH 

00 

rH 

r-n 

<—H 


CN CO 

rH 

p—i 

co 

CM 

CN 


CN CO 


£ 


r-1 

00 

rH 

c-~ 


rr 

N* 

CN 

in 

rH 

r- 

<T» 

e*- 

r- 

VO 

rr 

CN 

Tf 

r- 

CO 

CN 



>_^ 

r 



^—r 

<n 

m 

in 

00 

in 

ON 

CN 


r-i 

rH 

rH 

rH 

rH 

CN 


■E 

•rH 

6 


N. 





-o—** 

__ 

O 

vo 

vo 


-—s 

VO 

in 

r-i 

vo 

o 

in 

CT\ 

r- 

<Ti 

r- 

■'T 

CN 


in 


CO 

■—* 

>_✓ 

*'—" 

N_^ 


'—" 

•wp 

vo 

r- 

ro 

<n 

cn 

in 

00 



rH 



rH 

t— 1 



0 V 4 

in 


CO 

CN 

rH 

o 

Ov 

00 

r- 

vo 

in 


CO 

rj 0 

00 

00 

00 

00 

00 

00 

r- 

r' 

r- 

r- 


r» 

e'¬ 

a 0 

<Ti 

Ol 

OV 

<7\ 


CTV 

o> 

cn 

cn 

cn 

cn 

cn 

en 

Z >4 

r-i 

r —1 

r —1 

r—i 

rH 

i-H 

r—i 

i—( 

«-4 

r—i 

r—i 

r —1 

r—i 






Percentage of Catalyst Removal (and Sample Size) 
among Catalyst-equipped Vehicles by Model Year and Vehicle Age at Time of Survey 


<D 

MH 

•H 

o 

I— I 

o 

•H 

sz 

s 


<0 

p 


jC 

4-1 

c 

<\) 

> 

Q) 

W 


5 

C 

s 


5 

C 


jC 

cn| 

•rH 

Ed 


5 

s 

> 

£ 


5 

X 

•«H 

cn 


Id 


A 

B 

3 

£ 


£ 

•H 

6 


? 

o 

o 

£ 


4J 

E 

•H 

Dli 


- 34 - 


00 

o 

00 


r- 

VO 

in 

co 


(N 

(N 

in 

vo 


r-~ 

00 

VO 


CM 

r- 

in 

CM 


m 

in 


fN 

in 

CM 

CM 



.-, 

—• 

N. 

- — s 





r- 

r-~ 

o 

ov 



in 


<T\ 

in 

o 

CM 

rH 


o 


in 

rr 

CM 


r- 


CO 


__■ 

y — ■ 


"—* 



*,_. 


CM 

vo 

CO 

VO 

o 


CM 









VO 

in 


00 

p—» 


r-> 

r-~ 

00 

VO 

o 

CM 

in 


r—( 

r- 

VO 


CM 


in 



co 


— 


■s_r 

v —* 


>-" 

._■ 

o 

CM 

in 

CM 

** 


rH 

CM 


00 

rH 

in 

r—t 



in 


r- 

CM 

rr 

rH 



ov 


CM 


VO 



>.—^ 


__' 

'-" 

>_^ 



o 

CN 

rH 

CM 

CN 


o 

.__ 







CM 


o 

.—* 


vo 

rH 

VO 


uo 

r- 


CM 

<T\ 


rH 

CM 

m 


CO 

CM 

— + 

v 

•*—✓ 

^—* 


>_X 


o 

rH 

o 

o 


o 

O 


r- 

p—i 

rr 


Q) U 

in 


co 

CM 

rH 

o 

CTi 

00 

■g (0 

00 

00 

00 

00 

00 

00 

r- 

r- 

Q CD 

<T> 

<T> 

a\ 

o\ 

o> 

0>| 

o> 

ov 

S >4 

•—i 

i—i 

r— 1 

r—( 

rH 

r-4 

rH 

rH 


CTi 


VO 

r* 

<j\ 


o 

co 


CM 




»—• 


rH 

rr 


<T> 

r- 


CM 

rH 





in 

VO 


rH 

rH 




<7\ 


--% 

r- 

rH 

in 

CO 

ro 

r** 

V_^ 

— 

^— * 

r- 

CN 

CO 

r—( 

rH 

CM 


CM 


<T» 

<Ti 

r- 

in 

CO 

CO 


co 

r—1 

rH 

V_r 


__ 

^^ 

o 


CM 

CM 

rH 

rH 

(—( 

r—l 





vo 

VO 

r- 

- — » 

00 

VO 

in 

<7\ 


rH 

CM 

rH 

v_>> 


__■ 

«—' 

00 

rH 

VO 

VO 


rH 


CM 





CO 

rH 

.—* 


rH 

r- 

00 


CM 

CN 

■'* 


-- 




00 

CN 

o 




r—l 





^-V 

CM 

r-v 


•^r 

VO 

<T\ 


o 

co 

ID 


CM 

- ^ 



V_ * 


CN 


CM 


CM 

CM 

CM 


m 

r- 


Tampering rates have been rounded to the nearest whole percent. A zero does not necessarily indicate a total 
absence of tampering, but rather a level of tampering that rounded to zero. 






- 35 - 


permit any conclusions.) For example, the tampering incidence 
for 1979 vehicles increased from 6% in their first year to 
37% by their seventh year of use. This increase in tampering 
with vehicle age also seems to lessen once the vehicles of a 
model year are five years old or more, with the tampering 
rates leveling off at higher levels in older model years. 

This type of analysis involves observations made from different 
survey sites at different times; nevertheless, the relationship 
between tampering rate and vehicle age is readily apparent. 

Tables 9 and 10 can also be analyzed vertically (holding 
vehicle age constant), which provides a look at the tampering 
rates for different model year vehicles of the same age. 

This approach suggests that improvements in automotive tech¬ 
nology, such as closed loop emission control systems, may 
initially affect overall tampering rates. Vehicle tampering 
by the second year, for example, was only 2% for 1984 vehicles 
compared to 10% for 1977 vehicles. A similar vertical analysis 
of Table 10, however, shows that catalytic converters are as 
susceptible to tampering on newer models as on older ones at 
a given vehicle age. Vertical analysis of Tables 9 and 10 
introduces the same variability as the horizontal analysis. 

The influence of vehicle age on tampering can be more 
clearly seen when the data in Tables 9 and 10 is presented 
graphically. Figures 4 and 5 plot the overall and catalyst 


Tampering Rate (%) Survey Year 


- 36 - 


00 CD ' 

* & o s □ 


CD 


C\J 00 

00 <r1 00 n 

CD VJ CD ^ 


00 

CD 


□ 


ID 

00 ^ 
CD VI 


O 


< □ 


□ 


QD<J 

O <XO <] 


O *089 


•XO ®J □ <1 

]□ < 


-X-Oo 




O KCM- 


® a 




X 


J_I_I_i_L 


OJ 


CD 


00 


CD 


ID 


00 


C\J 


CD 

CO 


CD 

ID 


CD 


CD 

00 


a 

CM 


Vehicle Age (years) 

Figure 4. Cumulative tampering prevalence as 
function of vehicle age for the 
1979 - 1985 surveys. 





- 37 - 


L 

O 

cu 

>- 

OJ 

> 

L 

D 

LO 




Q) 

-4-> 

O 

ad 

CD 

c 

•H 

L 

QJ 

CL 

E 

O 

I— 


go o) t—• c\j m 

g * go g □ g <1 go 


GO 

CD 


□ 


ID 

CD ^ 
CD VI 



Vehicle Age (years) 

Figure 5. Cumulative catalyst tampering rate as 
a function of vehicle age for the 
1978 - 1985 surveys. 









- 38 - 


tampering rate, respectively, as a function of vehicle age 
for the 1978-1985 surveys. This is equivalent to the diagonal 
method of analysis used for Tables 9 and 10 that was outlined 
previously. Figure 4 demonstrates that the relationship 
between tampering rate and vehicle age is not only linear, 
but has remained nearly constant since the first survey in 
1978. The strong correlation is obvious despite the different 
sizes, vehicle compositions, and locations of the surveys. 

In Figure 5 the catalyst tampering rate remains negligible 
for the first two to three years of a vehicle's life, and 
then increases thereafter. This delay in catalyst tampering 
is understandable, since the emission control components on 
all new vehicles are warranted for 5 years/50,000 miles by 
the manufacturer, providing an incentive to maintain the 
catalysts on vehicles still under warranty. A similar delay 
in overall tampering would also be expected, but is not 
readily apparent in Figure 4. 

The link between tampering prevalence and vehicle age 
was shown to influence the survey averages for tampering in 
the 1984 report. Previous survey samples have been comprised 
of increasingly older vehicles, contributing to the increase 
in overall tampering among surveyed vehicles. Figure 6 shows 
that the proportion of older vehicles (five or more years 
old) in the survey declined in 1985 for the first time, down 
to 52% from a high of 58% of the vehicles surveyed in 1984. 


- 39 - 


(/) 0) 
OJ L 
O 

o 2 : 

•H 

_C L 
OJ o 

"O 
c+- —. 

O O 

-P (/) 
C L 

ai o 
a qj 
L >- 

a) 

CL LD 


o 


QJ 

-p 

o 

CL 

CD 

c 

•H 

L 

QJ 

CL 

E 

□ 


[] 


CD 

C 

•H 

L 

QJ 

CL 

E 

o oj 
1— -p 
□ 

-P CL 

c/) 

o 

-p 

o 

CJ 


' 

/ \ 



in 

00 

CD 


- 3 - 

GO 

CD 


CD 

00 

CJ) 


OJ 

CO 

CD 


00 

CD 


O 

00 

CJ) 


CJ) 

0- 

CJ) 


00 

e'¬ 

er) 


L 

a 

OJ 

>- 

OJ 

> 

L 

D 

cn 


L 

a ) 

CL 


CD 


in 


CD 


OJ 


Figure 6. Comparison of catalyst and overall 
tampering rates with vehicle age as 
a function of survey year. 








- 40 - 


This decline may represent a stabilizing of the proportion of 
older vehicles surveyed, since the 1985 survey population 
encompassed 82% of the cars and 74% of the light-duty trucks 
currently in use. 2 The lower proportion of older vehicles in 
the survey may have thus contributed to the decline in tampering. 

Manufacturer . Figure 7 presents the 1985 tampering 
rates for each major manufacturer. Since the number of 
vehicles surveyed for each individual foreign manufacturer 
is small, foreign vehicles have been combined into two 
groups, European and Japanese. As in previous surveys, the 
tampering rate is higher among domestic than foreign 
manufacturers. 

Figure 8 shows the trend in tampering rates for each 
manufacturer over time. The American vehicles are at or 
consistently above the overall tampering rate, while the 
European and Japanese vehicles have a tampering incidence 
consistently lower than the overall rate. 

A number of factors might explain the discrepancy in 
tampering among manufacturers. Differences in design may 
make some vehicles more tamper-prone than others. Changing 
market share history results in different age distributions 
for vehicles of different makes, and vehicle age is clearly 
related to tampering prevalence. Tampering rates probably 
vary with geographic location and socioeconomic background, 


2 based on model year distribution data used in MOBILE3. 




- 41 - 






18 % 




Tampering Rate (%) 


Figure 7. Tampering rates by manufacturer - 

1985 survey. 
























Tampering Rate (%) 


- 42 - 


CO 

CD 

r—1 

OJ 

00 


U0 

o 

17' 

00 

00 

00 

00 

00 

CD 

CD 

CD 

CD 

CD 

CD 

CD 

t— t 

r-H 

<—i 

*-« 

i-H 

»—< 

T—1 




0> 

CP 
o 
u 
0) 

■7 

0) 'S' 

IWWV] n\ ? 

rX w X c a 






i^z^z x z \z \/ y y y y .y y y yyyy 

rr^r x x 1 * L * 1 - - - - 






t. \ . .V-V- V \ \ 

\zzzzz 


, ^yysWAW// 6 


u 

0) 


in 

7- 

U 





, WW yyy 

l_. V \ . v - - - • L ' ' 



CXWT 


£ 


L 



O 


O 

00 


a 

oo 


o 


o 


i_ 

Q) 

L 

D 

-P 

O 

□ 

< 4 - 

D 

C 

a 


Figure 8. Tampering prevalence by manufacturer 
for the 1978 - 1985 surveys. 











































































- 43 - 


so the owner demographics for different makes may affect 
the likelihood of tampering. Finally, certain types of 
vehicles (trucks, for instance) are more likely to be 
tampered, and thus manufacturers with production concen¬ 
trated in these types can be expected to have higher 
tampering rates. 

5. I/M Programs and Geographic Bias 

Before examining the impact of I/M and antitampering 
programs on tampering and misfueling, the influence of 
geography on the survey data should first be discussed. 
Previous surveys have shown that tampering is historically 
higher in southern states than in northern states, which 
complicates any evaluation of I/M and antitampering program 
effectiveness. To illustrate this phenomenon the 1985 survey 
sites are listed below by program type. 


Non-I/M 

I/M-Only 

I/M + ATP 

Kansas City, MO 

Louisville, KY 

Fresno, CA 

Kansas City, KS 

Wilmington, DE 

Charlotte, NC 

Raleigh, NC 

Philadelphia, PA 

Northern Virginia 

Portland, ME 


Long Island, NY 

Cleveland, OH 



Baton Rouge, LA 



Albuquerque, NM 




The sites for the 1985 survey are fairly well distributed 
geographically among program types, lessening any geographic 
bias. The influence of geography can still be seen, however, 
in the tampering rates for the 1985 survey sites. The three 
areas surveyed with the lowest tampering rates were all 
northern cities (Portland, Philadelphia, and Wilmington). 






- 44 - 


Port land 's low tampering rate (12%) is particularly noteworthy 
because it is a non-l/M area, and its tampering rate was 
considerably less than was found in Louisville (23%) , a 
southern I/M area, and Baton Rouge (32%), a southern non-I/M 
location. 

One way to minimize geographic bias when evaluating 
program effectiveness is to compare programs within the same 
geographic region. Figure 9 compares catalyst tampering and 
fuel switching in three southern cities with different program 
types - Raleigh (non-I/M), Louisville (I/M-only), and Charlotte 
(I/M + ATP). This data shows that when geographic bias is 
minimized the effectiveness of I/M and I/M + ATP becomes 
apparent. While such comparisons as these overlook other 
variables such as program design and administration, the 
geographical location of a survey site is nonetheless a 
contributing factor to an area's tampering prevalance. 

6. Effect of I/M Programs on Tampering 

Inspection and maintenance (I/M) programs require vehicles 
to meet specific idle emission standards. Vehicles registered 
in areas with these programs are required to be periodically 
tested to assure that they comply with the specific idle 
emission cutpoints established by these jurisdictions. In 
addition to reducing emission levels by stimulating better 
owner maintenance, I/M programs may deter some tampering with 
emission control components. Data from previous surveys has 



- 45 - 




CD 

P 

O 

oz 

CD 

c 


L 

Q) 

Q_ 

E 

O 




>- 








O 








u 


* 



/-N 

z 


QJ 


* 

CL 


/^N 

r-H 


0J 

I— 


T 

.— t 

.— i 

p 

c 

JZ 

\ 

•rH 

c 

p 


CD*—• 

> 

o 

o 

+ 

•H 

1 

(0 

1 

rH 


Qi 

c 

•rH 

T 

L 

2 : 

rH 

o 

D 

\ 

O 

\ 

O 

c 

O 

►H 

JZ 

>-H 

oz 




CJ 




o in o 

c\j •—• •—• 


in o 


CD 

c 

.rH 

JZ 

o 

p 

• r-« 

CD 


01 

D 


U- 


L- 

O 

P 

o 

.r-* 

L- 

P 

U) 

Q) 

cd 



P 

0) 

p 

p 

0) 

> 

c 

o 

o 



o 

p 

o 

o 


p 

c 

dJ 

c 

o 

Q_ 

E 

o 

CJ 


CU 

QJ 

L 

JZ 

-P 


c 

o 


• rH 

•rH 



JZ 


XI 

CL 


c 

□ 


3 

L 


O 

CD 


Cp 

O 



CU 


CD 

CD 


c 



• rH 

CU 

• 

L. 

E 


CU 

□ 

CU 

Q_ 

(/) 

> 

E 


L 

□ 

CU 

D 

-P 

JZ 

(I) 


p 


Q- 


l n 

O 

c 

00 


•rH 

CD 

C 


i—i 

o 

(/) 


0) 

C 

1 

• rH 

o 


L_ 

• rH 

c 

O 

P 

o 

Q_ 

□ 

• H 

E 

O 

CD 

O 

O 

0) 

CJ 

.—i 

L 


CJ) 

CLI 

L 

D 

cn 

• rH 

Ll 

































- 46 - 


tended to support this proposition, since tampering in I/M 
areas has historically been lower than in non-I/M areas. 

Some I/M areas have also instituted antitampering 
programs (ATPs), which involve periodic vehicle inspections 
to check the integrity of specific emission control components. 
Antitampering programs vary greatly in the components inspected 
and the vehicle model years covered, so that a vehicle or 
component which would be inspected in one program area might 
not be inspected in a different program area. Successful 
antitampering programs should reduce existing tampering and 
deter future tampering with the components and model years 
covered by the program. 

Throughout this report the survey sites are classified very 
generally as seven non-I/M areas, three I/M-only areas, four 
I/M + ATP areas, and one ATP-only area (Houston) . Houston 
was the only city in 1985 to have an anti tampering program 
and no I/M program; similar programs, however, were implemented 
in other areas in January, 1986. The survey results from 
Houston will be discussed separately from the other survey 
sites. 

Table 11 compares the tampering rates in non-I/M, I/M-only, 
and I/M + ATP areas to earlier surveys. The tampering rates 
in non-I/M areas are considerably lower than in the previous 
two surveys, while tampering in I/M + ATP areas is higher 
than in previous surveys. It thus appears from the data for 
this particular survey that I/M programs and I/M + ATPs are 


- 47 - 


TABLE 11 



Tampering 

Prevalence 

in I/M and 

non-I/M Areas 


Survey 

Year 

non-I/M 

Tampering 
I/M-only 

Rate (%) 

I/M + ATP 

Overall 

1978 


19 

* 

* 

19 

1979 


20 

13 

* 

18 

1981** 


14 

* 

* 

14 

1982 


19 

15 

10 

17 

1983 


29 

24 

16 

26 

1984 


31 

17 

11 

22 

1985 


22 

17 

19 

20 

*none 

**1981 

surveyed 
survey was 

of limited 

scope, covering only two 

sites and 


399 vehicles 


TABLE 12 

Component-Specific Tampering by Inspection Program Type - 

1985 Survey 


Component 

Tampering Rate 
non-I/M I/M-only 

(%) 

I/M+ATP 

Catalytic Converter 

8 

3 

2 

Inlet Restrictor 

9 

5 

6 

PCV System 

5 

5 

6 

Air Pump System 

9 

6 

4 

Evaporative System 

4 

3 

4 


EGR System 


8 


6 


7 












- 48 - 


only slightly more effective than no I/M program at all. 
Similar results are reflected in the 1985 component-specific 
tampering rates for each program type, as shown in Table 12. 
These obseivdtlons are not due to any decrease in program 
effectiveness, but rather to the generalizations inherent in 
the way programs are categorized in this survey. 

Tampering programs vary generally in their model year and 
component coverage. Long Island, for example, is classified 
as an I/M + ATP site because 1984 and newer vehicles are 
subject to an antitampering inspection. Vehicles manufactured 
between 1975 and 1983, however, are subject only to an I/M 
test. Long Island is thus predominantly an I/M-only site. 
Also, all emission control components are not covered by the 
I/M + ATP inspection programs. For example, Charlotte does 
not inspect the evaporative system. Finally, Fresno is 
classified as on I/M + ATP area even though the tampering 
survey was conducted only six months after the start of a 
biennial inspection program. 

As this discussion suggests, the I/M + ATP rates reported 
above do not accurately reflect actual program effectiveness 
in controlling tampering with particular components in covered 
model years. In order to more appropriately assess the 
effectiveness of tampering inspection programs, the catalyst 
tampering rate will be analyzed. It is appropriate to focus 
on the catalyst rate for several reasons. The catalyst is 
the primary HC and CO emission control component and thus 


- 49 - 


represents the largest portion of the emission benefit 
attributable to tampering inspection programs. Also most of 
the survey vehicles were originally equipped with catalysts. 

Table 13 presents the model year specific and overall 
catalyst tampering rates for non-l/M, I/M only and I/M + ATP 
areas. All out-of-state vehicles were excluded from the I/M 
and I/M + ATP figures because those vehicles are not subject 
to the local programs. The New York vehicles were split by 
model year with the 1984 and newer vehicles appearing in the 
I/M + ATP rates and the 1975 to 1983 vehicles in the I/M only 
rates. To show the program impacts graphically, regression 
techniques were used to fit a separate power curve for each 
program type to the date in Table 13. These curves are presented 
in Figure 10. 

Figure 10 and Table 13 suggest that, for the sites 
surveyed, I/M and I/M + ATP areas have lower catalyst rates 
than non-I/M areas. The deterrence and correction of tampering 
in I/M + ATP areas is also readily apparent. 

7. Tampering Trends for Selected Sites 

The impact of I/M and antitampering programs in specific 
locations can be examined by comparing the 1985 survey data 
with that from earlier surveys. Comparisons made between 
surveys widely spaced in time, however, must take into con¬ 
sideration the differences in average vehicle age in each 
survey. The average miles traveled per vehicle surveyed in 
1985, for example, is 62% greater than it was in the 1978 



- 50 - 


TABLE 13 

Catalyst Tampering among Vehicles for each Model 
Year Covered by a Particular Program Type 


Vehicle 
Model Year 

Tampering Rate (%) 
non-I/M 

for each 
I/M-only 

Program Type 
I/M+ATP 

1985 

0 

0 

0 

1984 

0 

1 

0 

1983 

1 

0 

0 

1982 

2 

2 

1 

1981 

4 

2 

0 

1980 

9 

4 

2 

1979 

17 

• 

7 

4 

1978 

14 

7 

4 

1977 

25 

9 

3 

1976 

22 

12 

2 

1975 

32 

13 

10 

TOTAL 

8 

4 

1 






- 51 - 



i—i 


c 

o 

c 



CL 
I— 

c 

+ 


\ 

I—I 



p 

L_ 

Q) 

> 

C 

o 

o 




CD 


00 


[>- 


CD 


ld 




00 


OJ 


o 


CO 

L 

□ 

QJ 


OJ 

CO 

<c 

QJ 

i H 

O 

• H 

_C 

cu 

> 


U- 


o 



_□ 


c 


• 

o 

XI 


• rH 

cu 

cu 

P 

(_ 

> 

U 

cu 

L 

c 

> 

D 

D 

o 

(0 

<P 

o 

LD 

□ 

CO 

00 


cu 

CD 

(0 

r—1 

T—1 

o 

o 



•H 

1 

m_c 


c 

OJ 

(0 

• rH 

> 

E 

L 


□ 

CU 

L 

L 

CL 

O 

m 

E 

C|_ 

o 

□ 


L 

P 

CU 

CL 


CO 


L 

o 

P 

CU 


C 

P 

cu 

QJ 

L 

i—H 

L 

CU 

(J 

CU 

> 

•rH 

<P 

c 

_C 

4- 

o 

CU 

•rH 

C_) 

> 

X 


o 


cu 

L 

D 

CO 

•H 

Ll 


















- 52 - 


survey. Since vehicle age is directly related to tampering 
prevalence, a substantial increase in tampering might be expected 
to have occurred between 1978 and 1985, if all other factors 
remain constant (car/truck distribution, owner demographics, 
etc.) Inferences regarding program effects must thus be made 
cautiously. 

Figures ll(a)-ll(d) depict overall tampering rates for 
four sites surveyed in 1985 and earlier years. Figure 11(a) 
compares tampering in northern Virginia as found in the 1978 
and 1985 surveys. In 1978 northern Virginia was a non-I/M 
area. Figure 11(a) suggests that low tampering rates in 
northern Virginia predate the advent of an I/M + ATP, and that 
there has been essentially no change in overall tampering in 
northern Virginia since 1978. When the increase in average 
vehicle miles from 1978 to 1985 is considered, however, it is 
quite possible that tampering rates in Virginia in 1985 are 
much lower than they would have been without a control program. 

A similar comparison can be made in Wilmington over the same 
time period (Figure 11(b)). In 1978 Wilmington was also a 
non-I/M area, but had tampering rates that were much higher 
than in northern Virginia at that time. The institution of an 
I/M program in Wilmington has apparently had a significant 
impact on overall tampering, since the 1985 rates (for higher 
mileage vehicles) in Wilmington are equal to or lower than they 
were in 1978, when vehicle mileage was much lower. 


- 53 - 


Tampering Rato (2) 



a) Northern Virginia 


Tampering Rate (2) 



b) Wilmington. DE 

Figures 11(a) and (b). Comparison of data from 

1985 survey sites that had been 
surveyed previously. 

♦Fuel switching rates in 1978 do not Include 
plumbtesmo results 


cm cm 








































- 54 - 


Taraporing Rato (2) 




1982 


] 1985 


c) Baton Rougo, LA 


Tamporing Rato (2) 



1984 

(Now 


□ 1985 
(NYC 


York Cil 
Suburbs! 


d) Now York Motropolitan Area 

Figures 11(c) and (d). Comparison of data from 

1985 survey sites that had been 
surveyed previously (cont'd). 














































- 55 - 


Baton Rouge was surveyed in 1982 and 1985, and the 
results from those surveys can be found in Figure 11(c). 

Baton Rouge has always been a non-I/M area, and Figure 11(c) 
depicts a substantial increase in tampering in the absence of 
any control program. This difference may also in part be due 
to the higher average mileage of surveyed vehicles in 1985 
than in 1982, and the greater proportion of trucks surveyed 
in 1985. Baton Rouge instituted an ATP-only in September, 
1985, and is scheduled to be surveyed in 1986. 

Figure 11(d) shows the survey results for New York City 
in 1984 and its suburbs in 1985. The most interesting aspect 
of this comparison is the large decrease in the percent of 
vehicles with leaded fuel in their tanks. This may be attri¬ 
buted to a concentrated Agency and local effort to curb 
widespread unleaded gasoline contamination in the New York 
City area last year. 

8. Effectiveness of ATP-Only - Houston 

As was mentioned earlier, Houston (Harris County) was 
the first area to adopt an antitampering program without an 
idle emissions test. Started in July, 1984, this program 
includes a tampering check of the PCV, evaporative, air pump, 

and EGR systems for 1975 and later vehicles, and also a check 

% 

of the converter, inlet restrictor, and Plumbtesmo for 1980 
and later vehicles. To investigate the effectiveness of 
Houston's program, the 1985 tampering data for the components 



- 56 - 


and model years covered can be compared to similar data from 
the 1983 survey in Houston (see Table 14). The data presented 
in Table 14 is from all vehicles surveyed in Houston, including 
any non-Harris County vehicles that were surveyed. It is 
obvious that Houston's ATP program has noticeably reduced 
tampering for almost every component covered. As more 
antitampering-only programs are enacted nationwide, their 
effectiveness will be carefully evaluated. 

9. Correlation between Tampering and Idle Emissions 

As was mentioned previously, vehicles which are subject 
to an I/M program must meet specific idle emissions cutpoints. 
To assess the relationship between tampering and fuel switch¬ 
ing and idle failure rates, the idle emissions from vehicles 
have been tested against the cutpoints established by the 
I/M program where they were sampled. Vehicles in non-I/M 
areas were tested against the cutpoints specified by the New 
Jersey I/M program. The cutpoints for each I/M area are 
listed in Appendix C. 

The results of the idle tests are presented in Figure 12 
for vehicles in the various tampering and fuel switching 
categories. Only 14% of the surveyed vehicles that were free 
of tampering and fuel switching failed an idle test, while 
65% of the tampered and fuel switched vehicles failed that 


test. These results indicate that a substantially larger 




-57- 


TABLE 14 

Comparison of Tampering Rates in Houston* for Components 
and Model Years covered by Anti tampering Program 


Component and Model Years 

Survey Year 

1983 1985 

Catalytic Converter 1980+ 

6% 2% 

Inlet Restrictor 1980+ 

1 1 

Positive Plumbtesmo 1980+ 

7 2 

PCV System 1975+ 

9 5 

Evaporative System 1975+ 

8 4 

Air Pump System 1975+ 

9 8 


* averages include any non-Harris County vehicles that were 
surveyed. The 1985 rates for Harris County vehicles only 
are egual to or lower than those listed above 





Distribution of Survey Sample Among Tampering*. 
Fuel Switching, and Idle Test Categories 


- 58 - 



★ 


excludes malfunctioning vehicles (1% of total) 



































































































- 59 - 


proportion of tampered and fuel switched vehicles than of 
okay vehicles fail an idle test at typical I/M cutpoints. 

This is partly due to the tendency for tampered vehicles to 
have misadjusted carburetors, as is shown in Figure 13. This 
Venn diagram shows that 73% of the tampered vehicles with 
conventional carburetors also had missing sealed plugs or 
limiter caps. It must be noted from Figure 12, however, that 
35% of the tampered and fuel switched vehicles were still 
able to pass the idle test. 

Table 15 shows the percentage of vehicles that failed 

i • 

the idle emissions test for each vehicle condition. The 
failure rates are listed for the entire survey, as well as 
in two model year groupings representing "old" technology 
(1975-1980) and "new" technology (1981+) vehicles. "New" 
technology signifies closed loop emissions control, which 
came into widespread usage in 1981 model year vehicles. 

The overall failure rate for HC from tampered vehicles 
was nearly four times greater than for okay vehicles, and was 
three times greater for CO emissions. Over 40% of the vehicles 
that either had been fuel switched or had their catalysts 
removed also exceeded HC and CO limits. Conversely, nearly 
60% of the vehicles with missing catalysts or classified as 
fuel switched were still able to pass an idle emissions test. 
Interestingly, a significant number of arguably tampered 
vehicles also produced excess idle emissions. Since the 



- 60 - 


Carbureted Vehicles 

Carbureted vehicles with with Arguably 

some kind of tampering Tampered Carburetors 



Figure 13. Overlap of Tampering and carburetor misadjustment among conventionally 
carbureted vehicles - 1985 survey. 








- 61 - 


majority of arguable tampering involves idle speed limiter 
caps and sealed plugs, the high failure rate demonstrates the 
adverse idle emissions impact of improperly adjusted 
carburetors. 

The effectiveness of idle emissions testing on "new" 
technology vehicles can also be seen in Table 15. Idle 
emissions testing is considerably more effective in identifying 
tampering on 1980 and older vehicles than on 1981 and newer 
vehicles. It is particularly interesting that only one-quarter 
of the 1981 and newer vehicles surveyed which had missing 
catalysts or had been fuel switched would fail an idle emissions 
test. This suggests that idle emissions testing may not be 
an effective strategy for identifying tampering and fuel 
switching among "new" technology vehicles, since many vehicles 
with closed loop systems are able to produce low idle emissions 
even with a missing or inactive catalyst. The Agency has 
consistently advised I/M programs not to rely on idle emissions 
testing for these vehicles for this reason. 

The mean idle emissions for tampered and okay vehicles 
are presented in Table 16 by program type. The mean idle 
emissions from tampered vehicles were considerably higher 
than from okay vehicles. Overall, HC emissions from tampered 
vehicles were more than six times greater on average than for 
okay vehicles, while CO emissions were almost seven times 
greater. The means for non-I/M areas were higher than for 
I/M-only and I/M + ATP areas. 


- 62 - 


TABLE 15 

Idle Test Failure Rates (percent) by Pollutant 

and vehicle Condition 


Failure Rate (%) by Pollutant 
for Model Years listed 


Vehicle Condition 

1975 

HC 

-80 

CO 

1981 + 

HC CO 

Overall 
HC CO 

Okay 

19 

16 

8 

7 

10 

8 

Arguably Tampered 

31 

38 

15 

16 

26 

31 

Tampered 

42 

45 

27 

19 

39 

40 

Catalyst Removed 
or Fuel Switched 

45 

49 

26 

21 

42 

44 


TABLE 16 

Mean Idle Emissions by Vehicle Condition 


Survey 

Sites 


HC emissions(ppm) CO emissions(%) 

Tampered Okay Tampered Okay 


non-I/M 

341.0 

51.9 

3.0 

0.3 

I/M only 

243.9 

41.8 

2.2 

0.3 

I/M + ATP 

238.3 

40.3 

1.9 

0.3 

ATP-only 

306.4 

36.5 

3.2 

0.3 

OVERALL 

296.8 

45.9 

2.6 

0.3 











- 63 - 


To investigate the relationship between I/M programs and 
idle emissions, the emissions from okay and tampered vehicles 
in each program type can be compared (see Table 16). The 
data indicates that idle HC emissions from okay vehicles in 
I/M areas were 19% lower than from vehicles in non-I/M areas. 
There was no difference in this survey between idle CO emissions 
from I/M areas and those from non-I/M areas. The presence of 
an anti tampering program further lowered idle HC and CO 
emissions from okay vehicles. Idle HC and CO emissions from 
tampered vehicles were 28% and 27% lower, respectively, in 
I/M-only areas than in non-I/M areas, suggesting that I/M 
programs may reduce idle emissions from vehicles for which 
tampering is not successfully deterred. 

B. FUEL SWITCHING 

1. Fuel Switching Indicators and Overlap 

Fuel switching is more easily defined than measured, 
since no single indicator can accurately determine its 
prevalence. Since 1981 the surveys have used a combination 
of three indicators to measure fuel switching more accurately: 
a tampered fuel filler inlet restrictor, a positive Plumbtesmo 
test for lead deposits in the tailpipe, and a gasoline lead 
concentration of more than 0.05 gram per gallon (gpg). Of 
these three indicators, only a tampered inlet restrictor is 
also considered tampering, and as such is used to calculate 



- 64 - 


both tampering and fuel switching rates. Since false positive 
indications should be extremely rare for these measures, the 
percentage of vehicles with at least one positive indicator 
is a reasonable minimum estimate of fuel switching. 

The presence of any of these three indicators suggests 
that a given vehicle has been misfueled; their absence, how¬ 
ever, does not rule it out. For example, fuel samples could 
only be obtained from 83% of the unleaded vehicles surveyed, 
limiting the scope of this variable. A vehicle misfueled 
repeatedly with leaded gasoline may also have little detect¬ 
able lead in its fuel tank due to subsequent proper fueling. 
Similarly, a vehicle with an untampered fuel filler inlet 
restrictor may have been fueled at a leaded pump equipped 
with a smaller nozzle, or by using a funnel or similar device. 
The tailpipe lead test, due to the difficulties of field 
administration, may also fail to identify misfueling, and 
older vehicles may have had their tailpipes replaced since 
last operated on leaded fuel. As the lead phasedown program 
lowers lead levels in leaded gasoline, the incidence of false 
negative Plumbtesmo results may increase. The uncertainty in 
these measures, then, is always toward underestimating the 
number of vehicles misfueled. 

The limitations of the fuel switching indicators can be 
seen in their incomplete overlap. The results from these 
indicators would be expected to overlap significantly, since 


- 65 - 


they are three indicators of the same phenomenon. This has 
not held true, however, in the 1985 survey or in previous 
surveys. The Venn diagram (Figure 14) illustrates the degree 
of overlap in the 1985 results. For example, only 77% of 
the vehicles having leaded fuel in their tank also registered 
a positive Plumbtesmo test. Additionally, only 45% of the 
vehicles with tampered inlet restrictors actually had leaded 
gasoline in their tanks at the time of the survey. The 
incomplete overlap reflects the limitations of each indicator 
as well as the different aspects of fuel switching each 
indicator identifies. 

2. Fuel Switching Rates 

Of the vehicles requiring unleaded fuel, 9% were 
identified as misfueled by at least one of the indicators 
discussed above. The fuel switching incidence by survey site 
and program type is listed in Table 17. Non-I/M sites had 
the highest fuel switching rate (12%), followed by I/M + ATP 
areas and I/M-only areas. The prevalence of each fuel switching 
indicator in non-I/M areas is approximately double that found 
in areas with control programs. 

Tables 18 and 19 compare the fuel switching rates from 
the 1985 survey with those from previous surveys. As the 
tables indicate, the data from this survey show a general 
pattern of decline in fuel switching. Since such a pattern 
could result from the selection of sites surveyed this year, 
strong conclusions must await the data from subsequent surveys. 



- 66 - 


Leaded Fuel in Tank 
(274 Total) 



Positive Plumbtesmo 
(298 Total) 


Figure 14 . Overlap of fuel switching indicators among unleaded vehicles - 1985 Survey 







- 67 - 


TABLE 17 

Fuel Switching Rates among Unleaded Vehicles by Site 

and Indicator - 1985 Survey 


Survey 

Location 


Leaded Tampered 

Fuel in Inlet 

Tank(%) Restrictor(%) 


Positive >1 Positive 
Plumbtesmo Indicators 
(%) (%) 


Kansas City, MO 
Kansas City, KS 
Raleigh, NC 
Portland, ME 
Cleveland, OH 
Baton Rouge, LA 
Albuquerque, NM 
ALL NON-I/M SITES 

Louisville, KY 
Wilmington, DE 
Philadelphia, PA 
ALL I/M ONLY SITES 


6 

9 

11 

2 

3 

13 

5 
7 

6 
1 
1 
3 


Non-I/M Areas 
9 

10 

11 

4 

7 
17 

9 

9 

I/M Only Areas 

8 
3 
2 

5 


6 

7 

9 

1 

4 
14 

5 
7 

6 
2 
1 
3 


10 

12 

14 

5 

8 

21 

11 

12 

10 

5 
3 

6 


Fresno, CA 
Charlotte, NC 
N. Virginia 
Long Island, NY 
ALL I/M+ATP SITES 
HOUSTON, TX (ATP ONLY) 
ALL SITES 


2 

3 

2 

5 

3 

4 

5 


I/M + ATP Areas 

9 

5 
4 

4 

6 

5 
7 


1 

3 
1 

4 
2 

5 
5 


9 

6 

4 

7 

7 

7 

9 










- 68 - 


TABLE 18 

Fuel Switching Prevalence among Unleaded Vehicles 

in I/M and non-I/M Areas 

Survey Fuel Switching Rate (%) 


Year non-I/M 

I/M 

only 

I/M + ATP 

Overall 

1978* 

4 



NS 

NS 

4 

1979* 

12 



3 

NS 

9 

1981** 

16 



NS 

NS 

16 

1982 

15 



7 

2* 

11 

1983 

17 



12 

5 

14 

1984 

19 



10 

8 

14 

1985 

12 



6 

7 

9 

Plumbtesmo test 
1981 survey was 
399 vehicles. 

not 

of 

used. 

limited scope, 

covering only 

two sites 


NS: None surveyed 


TABLE 19 


Fuel Switching Rates among Unleaded Vehicles 
by Indicator and Survey Year 


Survey Leaded Fuel Tampered Inlet 
Year in Tank(%) Restrictor(%) 


Positive 
Plumbtesmo(%) 


>1 Positive 
Indicators(%) 


1978 4 

1979 10 

1981 7 

1982 6 

1983 7 

1984 8 

1985 5 


3 

4 
6 
6 
7 

10 

7 


* 

* 

8 

7 

10 

9 

5 


4 

9 

16 

11 

14 

14 

9 


*Plumbtesmo test not used 













- 69 - 


Table 20 presents the combined tampering and fuel 
switching rates for the 1985 survey. The percentage of 
vehicles that were tampered or fuel switched was 21%, only 
1% higher than the tampering rate alone. The substantial 
overlap between the tampering or fuel switching rate and 
the tampering rate alone results mainly from the inlet 
restrictor tampering rates being used to calculate both 
values. Table 20 also demonstrates that approximately half 
of all tampering and fuel switching is composed of vehicles 
in the catalyst removed or fuel switched category. This 
indicates the very serious nature of most tampering. 

3. Fuel Switching by Vehicle Type 

As was reported previously, the fuel switching rates for 
trucks was considerably higher than for passenger cars - 13% 
vs. 8% (Table 1). The filler neck restrictor tampering 
rates were also higher for trucks than for passenger cars 
(Table 1). 

4. Fuel Switching and Vehicle Age 

Table 21 correlates vehicle age and model year with fuel 
switching rates for the 1978-1985 surveys. This method of 
analysis is identical to the one used earlier to compare 
tampering rates across model years and vehicle ages. Analyzing 
Table 21 diagonally shows that the rate of fuel switching 




- 70 - 


TABLE 20 


Combined Tampering and Fuel Switching Rates 


1985 Survey 


Survey 

Location 


Catalyst-equipped vehicles 
with catalysts removed or 
fuel switched (%) 


Unleaded vehicles 
either tampered or 
fuel switched (%) 


Non-I/M Areas 


Kansas City, MO 

12 

22 

Kansas City, KS 

12 

27 

Raleigh, NC 

15 

20 

Portland, ME 

6 

14 

Cleveland, OH 

11 

23 

Baton Rouge, LA 

20 

33 

Albuquerque, NM 

11 

25 

ALL NON-I/M SITES 

12 

I/M-only Areas 

23 

Louisville, KY 

10 

24 

Wilmington, DE 

6 

15 

Philadelphia, PA 

3 

14 

ALL I/M-ONLY SITES 

6 

I/M + ATP Areas 

17 

Fresno, CA 

10 

22 

Charlotte, NC 

6 

19 

N. Virginia 

5 

15 

Long Island, NY 

9 

22 

ALL I/M + ATP SITES 

8 

20 

HOUSTON, TX (ATP ONLY) 

9 

19 

ALL SITES 

10 

21 









Plunbtesmo not used in 1978 and 1979 surveys. 




- 72 - 


increased with vehicle age in every survey taken. A similar 
though less pronounced pattern can be seen when the data is 
analyzed within model years (horizontally) or within vehicle 
age groups (vertically). 

5. Catalyst Tampering and Fuel Switching 

Consumers and mechanics remove catalytic converters for 
a number of reasons, but much of their motivation is related 
to fuel switching. The vehicle owner may remove the catalytic 
converter either prior to misfueling, or after some misfueling 
if the vehicle's driveability has been adversely affected by a 
catalyst damaged from the repeated misfueling. The data from 
this survey cannot be used to distinguish between these two 
situations, but can be used to examine the extent to which 
these types of abuse occur in conjunction. 

Of the catalyst-equipped vehicles surveyed, 10% were 
either catalyst tampered or fuel switched (Table 20). The 
rates in non-I/M, I/M-only, and I/M + ATP areas were 12%, 

6%, and 8%, respectively. 

Figure 15 depicts the degree of overlap between catalyst 
removal and fuel switching. Vehicles with catalyst tampering 
exclusive of fuel switching were relatively uncommon — only 
one-third of the catalyst tampered vehicles were not fuel 
switched. Fuel switching, however, is not always accompanied 
by catalyst removal, since 61% of the fuel switched vehicles 
still had their catalysts. 



- 73 - 


Catalyst Tampering 


Fuel Switching 



Figure 15 „ Overlap of catalyst tampering - and fuel switching among catalyst-equipped 
vehicles - 1985 Survey. 


Percentage of Misfueled Vehicles 



Gasoline Lead Concentration (grams/gal Ion) 

Figure 16. Lead concentrations in fuel sampled 

from misfueled vehicles. 







































- 74 - 


6. Gasoline Lead Concentrations 

Of the vehicles identified by any of the three indicators 
as raisfueled, 46% had only trace amounts of lead (less than 
0.05 gpg) in their gasoline when inspected. These vehicles, 
then, were identified as fuel switched by a tampered filler 
restrictor and/or a positive Plumbtesmo test. Figure 16 
presents the distribution of lead concentrations of 0.05 gpg 
or more in misfueled vehicles. The impact of lead phasedown 
can be dramatically seen when Figure 16 is compared to similar 
data from the 1984 survey. In the 1984 survey 39% of the 
misfueled vehicles had a gasoline lead concentration in 
excess of 1.0 gpg, compared to 1% in 1985. The distribution 
of lead concentrations in 1985 is centered on the 0.4-0.6 
gpg range, which coincides with the interim lead limit of 0.5 
gpg in effect between July, 1985 and December, 1985. 



- 75 - 


APPENDIX A 

RELEVANT PORTIONS OF THE CLEAN AIR ACT 

Section 203(a)(3): The following acts and the causing thereof 

are prohibited — 

(A) for any person to remove or render inoperative any device 
or element of design installed on or in a motor vehicle or 
motor vehicle engine in compliance with regulations under this 
title prior to its sale and delivery to the ultimate purchaser, 
or for any manufacturer or dealer knowingly to remove or 
render inoperative any such device or element of design after 
such sale and delivery to the ultimate purchaser; or 

(B) for any person engaged in the business of repairing, 
servicing, selling, leasing, or trading motor vehicles or 
motor vehicle engines, or who operates a fleet of motor 
vehicles, knowingly to remove or render inoperative any 
device or element of design installed on or in a motor 
vehicle or motor vehicle engine in compliance with regulations 
under this title following its sale and delivery to the 
ultimate purchaser. 


- 76 - 


APPENDIX B 

SURVEY AND DATA RECORDING PROCEDURES 
1. Explanation of Survey Forms 

The forms on the following pages were used for recording 
the survey data in the field. The forms were forced choice to 
ensure coding consistency, and were designed to facilitate 
direct data entry. The following codes were used to record 
data for the major system components on the data sheets: 

0 - Not originally equipped 

1 - Functioning properly 

2 - Electrical disconnect 

3 - Vacuum disconnect 

4 - Mechanical disconnect 

5 - Incorrectly routed hose 

6 - Disconnect/Modification 

7 - Missing item 

8 - Misadjusted item 

9 - Malfunctioning 

A - Stock equipment 

B - Non-stock 

D - Add on equipment 

Y - Yes 

Z - No 

Additional codes were used for those components which 
could not be classified into the above categories. A brief 
description of each data entry follows. 



1985 TAMPERING SURVEY - PART A (UNDERHOOD) 


- 77 - 


ui 

Q. 

> 

fr¬ 

ee 

o 

fr- 

< 

tr 

3 

a 

ec 

< 

o 


o 

o 


o 


o 

o 


x 

u 

o 


c 

2 


5 2 £ 

cb iL cb 


0 

f 

S'? K 
o ^ 

• 

• u o» 
• o 
• ^ u 
m e a 
m ** ** 
w u • 

a. oh *j 

< *» S 8 

O 2-.2 


a 

• 

X 

u 

U M 

• o 
a 

a e • 
o • • 

U J< u 

« O 
«4 M 

".CS 
•g-s s 
252 


gA A * * 


* 

*4 

* 

• 

• 

w -O 

•o 3 

2 2 

fl • 

9 M 

Tl £ 

<9 tfl 
• 9 

«4 

X Ob 

ob 


□ !□ 


flfr 

0 


&x 


I X"b >% 


2 H fl i *4 

Ui g.| 8 S 

H • w a 0 

_0 . 8 w 8 

E> 2 *°- 

<• S 


u 


o 

o 


g 


o • u 


ox 
ui o 

<**d> 

*o 

r ui 
^ *» 


u y « • 

*»•*■§ w n 


* 

J- 


?!□ 


frl* 


3 


o 

S 

1 5- 

U 9 

<r 

• • 


%4 U 

ft. 5 £ 

a 


e 

w> 


o 

0 

3 


UJ 

> 

_J 

< 

> 

_l 

o 

cc 


O 

O 

CC 

o 

III 

o 

0 


*0 

o. 


3 

cr 


2 

<J> 


w 

• 

a. 

o 


4i 

U 

* 

S 

O 

o 


o 

o 


u 

u 


w 

9 4 

« m 
m a 

• Cb 
U «4 

Ob 9 
I O* 

^ • 

y 


u 

o 


J 9 


o 

c 

3 


X 

u 


3 

>• 2 
rA i 




a 


_ • u • 

OC u o u 

oS „ 2 

»2 2 Z 

Z o 

A 

0 

3 □ 


l 


8 ? 


« 3 


9 i-» 

I s 


M ^ 


9 ^0 


e n 




ii 

eb 


_ g x *3 

58.!? 3 I 

3 U w 1 

v u • 8 

• o £ 

• 3 l< ■ u 
M « b «« M 

““ ”*1 


.J 

U tf 


m m 

o wo 


5 □ ?□ 


5 

8 


a 

UI 
»- 
a 

® u a 2 o S 5 

a. 2:1 25a 23 
a 

3 

a. 


3 3 

3 M 
** e 

M 


^ frl dt 


O 

UL 


2 


0 

CC 


© “ 
3 3 


1 


* K 

u r 

04 Of) 

J $ 


> « 


rA iA rl 


ui 


O g. 

w • 

z 

W 5 

01 w 

W O 

Cl u 

2 


UI 


>b 

M 


U 

c 

2 

r 



- ! 


5 2 
o“ 


W 

0 


□ 


1 


w 

o 


e 

3 


A 

g 


< x 3 

* * i 

fr. m s 

5 ± ob 

< 

X 


ee 

o 

0 

z 

UI 

0 


0 

e 


!□ £□ 


o 

4# 

2 

6 A 


a U X • 

• 09 

2 2 2 2 

cb xA- 


S 

: 


UI 

X 

< 

fr¬ 


ee 

< 

a 

ui 

H 

< 

UI 

X 


I 

flfc 

«4 

9 


W 

2L 

O 

u 


9 w 

2 i 

d> A 

□ 


frA xA- 


?.4s! 

• fl • u 

•2233^ 

5 04 u G u 

urn u w | 

3111335 

rl d) Jb o 

> 

o 

OL 


U U 4N 


« o 

2 I 


!i 

04 04 

^ * M 

.25 31 

2 2 3 i I 

222 2 3 


3 

<u <-* 

• • 

85 

X « 

8 k 


A A <1* 

□ 



• 8 * 

8 -2 
5 . 3 

44 

to u u 

5 §3 

• 4« i 

• *4 • 

2 23 

rs dr> 



e 

Q 


0 



• W 

8 . 
w • 

04 

23 



3NC 


■ 


ec 

ui 


< 

UI 

_l 

o 

ee 

< 



0 

o 






























1985 TAMPERING SURVEY - PART B (REAR) 


- 78 - 


UJ 

m 

< 

j 

x 

z 

< 

h 

C0 


T3 

V 
cu 
cu 

t4 

% 

V 


60 

*H 

U 

O 

u 

* 


T3 

V 

O. 

CU 


3 


M 
41 
CU 
O « 

CU U 

a to 

• 4) C 
4J W -H 

o «i m 

cup 

^ ti. 


JCcc 3- 
Oo . 

Uli_ oo 

Zo * 

CCqc u 
tui— £ 

dSi 

U-X 


u 

V 

cu 

o 

u 

CU 


u 

o 

c 

3 

(M 


T3 

<u 

C 

0) 

-o 


o 

V) 


JS 

u 

9) 

X 


a 

<u 


60 

c 

•H 

« 

0) 


rL 


CO 

LU 

H 

CD 


> 

•H 

U 

•r» 

w 

o 

CU, 

oL 


LU 


i < 

s « 

60 

£ 

LL 


n 

O 

>* 

z 

si. 

rb 



CM 


CO 


’'t 



CO 


CO 


CO 



< 

H 

< 

O 

_J 

UJ 

3 

LL 



jc 

c 

«4 


00 

n 


lO 

CO 


< 

m 


o 

a 


> 

M 

o 


X 

o 


o 

« 

o 

•> 

o 

w 

X 

►- 

* 

o 

X 

o 


LU 


UJ 

CD 

< 

—I 

X 

CO 

< 

Q 

CO 

CM 


T3 

« 

CU 

CU 

•H 

3 

©• 

4) 


u 

o 

u 

o 

Z 


§ 


u 

41 
Cu 
O U 
U /-> t4 
CU il 

O 60 

• vc 

U VI <H 

u « n 
fl u » 
a cu-h 
hvX 


I, 




X 

UJ 


o 

o 

o 

H 

> 

_J 

< 

H 

< 

O 


CM 


T3 

4> 

cu 

CU 

>, 


2 

Ul 

H 

CO 



2 

UJ 

H 

CO 

n 

>* «0 


<H 

3 

H 

U 


> 



>■ 

w > 

rl 41 60 Ul 

U •—l C C 

O* 

41 

V 

cu 

a 

41 

CO 



4) -H 

cu m fl 

41 

*5 X 

• 

o 

Ul 

u 

X-N *H 

1— 



l-H” 

0 3 0 
M O u-t 

•H “ 

£ < 

60 

•H 

Ul 

O 

CU 4J 

a oo 
• « G 

U 0) *H 

CO 

3 


a 

o 

u 

Ul 

cos 

<UJ 

Sh 

a-H li 

> o 

• lO C 
0 0 3 

d) ^ 

o 

01 w 

J* 

JJ 

o 

fl 

a) vi 

Ui 01 

< 

u 

o 

i 

e 

U «M 

C O 1-1 

*4 V/ 
V 

O 

z 

(2 

53 

X 

4J 

Ul 

o 

z 

«2£:2 

H 2 
A— 


4, 

ri. 

X 

UJ 

«fc 

ob 

x z 

LU— 

A ch 

< 

H 




co 



0) 


O 




CM 



CM 


CO 


3 

O 

X 


u 

V 

CL 

o 

u 

o. 


o 

e 

3 

u, 


a 

V 

u 


60 

e 

0) 

V) 


ri. 


60 

c 

•H 

c 

o 


u 

c 

3 


<4 

r 


o 

o 


X 





UJ 





CD 

2 

u 

UJ o 

-1 3 

UJ ° 


<n 

fl 

«4 

> 

z 


Q « 


«0 

4) 



° t 


TJ 

3 

o 

v~s 

Ul 

O 



> 

H 

UJ 

-J 

O 


Ul 


u 

10 

o 

ci> 


o 

3 

u 

H 


UJ 

H 

< 


UJ 

CO 


o 

X 

uu 

-J £ 

oS; 


o 

o 

UJ 


X 

UJ 

H 

Ul 

O 

Q 


3 

O 


in 


0) co 


LU <u 


o> 

LJ H 


OS 




J w 

•J N-/ 




CM 



^4 














CO 


O 

CO 


Ul 

04 









































- 79 - 


Form A - Underhood 

1-4 ID Number - Vehicles are numbered sequentially as 
they are inspected. This number is preceded by a 
site identifying letter. 

5-8 Month and year of last I/M inspection (left blank 
if vehicle is licensed in non-I/M area). 

9-12 Displacement - as recorded on the underhood emission 
label. 

13-14 Vehicle Model year 

15-25 Engine Family - as recorded on the underhood emission 
1abel. 

26-36 Non-serial number portion of VIN - as recorded on the 
driver's side of the dash under the windshield or the 
driver's door post. The VIN is recorded only if the 
engine family can not be determined. 

37 Originally Catalyst Equipped - as recorded on the 
underhood emission label or the driver's door post. 

38 Air Cleaner - is coded 'A', 'B', or '7'. 



- 80 - 


39 Heated Air Intake - provides warm air to the carburetor 
during cold engine operation. The heated air intake 

is coded 'O', '1', '3', '4', '7' (stovepipe hose), 

'9' (vacuum override), or 'B' (custom air cleaner). 

40 Positive Crankcase Ventilation (PCV) system - prevents 
crankcase emissions by purging the crankcase of blow- 
by gases which leak between the piston rings and the 
cylinder wall in the combustion chamber under high 
pressures. The PCV system is coded '1', '3', '4' 

(fresh air hose), '7', or 'B' (includes fuel economy 
devices) . 

41 Turbocharger - coded 'O', 'A', 'B', or 'D'. 

42 Evaporative Control System (ECS) - controls vapors 

* 

from the fuel tank and carburetor. Some systems have 
two lines: from the fuel tank to the canister, and 
from the canister to the carburetor or air cleaner 
(for purging the canister). Other systems have a 
third line connected to the carburetor. The ECS is 
coded '1', '3' (carburetor line), '4' (tank 
line), '5', '7', or '9' (air cleaner unsealed). 

Air Injection System - extends the combustion process 
into the engine's exhaust system by injecting fresh 
air into the exhaust ports, lowering exnaust emissions 
while still maintaining proper vehicle performance. 


- 81 - 


Two types of air injection systems are currently used. 
One type uses a belt-driven air pump to direct air 
through a control valve and into the exhaust manifold. 
The other type is a Pulse Air Injection Reaction 
(PAIR) system, which uses an aspirator commonly 
located in the air cleaner to supply air to the exhaust 
manifold. 

43 PAIR - coded 'O' (if air pump system or none), '1', 

'4', '7', or '9'. 

44 Air Pump Belt - is coded ’O' (if PAIR), *1', '7', or 

'8' (loose belt). 

45 Air Pump System - for the purposes of this variable, 
consists of the air pump and control valve and is 
coded 'O' (if a PAIR or none), '1', '4' (excluding 
belt removal), '7', or '9'. 

46 Exhaust Manifold - coded 'A' or 'B*. 

47 Oxygen Sensor - Controls the air-fuel mixture going 
into the engine of vehicles equipped with three-way 
catalytic converters. The sensor is coded 'O', 


’ 2 ' , 


'4' (unscrewed), or '7'. 


- 82 - 


48 Carburetor Type - is coded 'S' (sealed plugs covering 
mixture adjustment), 'F' (fuel injection), 'A', 

or 'B'. 

49 Limiter Caps - plastic caps on the idle mixture screws 
to limit carburetor adjustments. The limiter caps 
are coded 'O', '1', '4' (tabs broken or bent), '7', 

or '8' (sealed plugs removed). 

Exhaust Gas Recirculation (EGR) System - directs a 
portion of the exhaust gases back into the cylinders 
to reduce N0 X emissions in the exhaust gas. The 
standard EGR configuration consists of a vacuum line 
from the carburetor to a sensor (used to detect 
engine operating temperature to activate the EGR 
valve), and another vacuum line from the sensor to 
the EGR valve. 

50 EGR Control Valve - coded 'O', '1', '3', '4', or '7'. 

51 EGR Sensor - coded 'O', '1', '3', '5', '7'. 

52 Computer Systems and Related Sensors - computerized 
engine and emissions control system which receives 
input from various sensors for engine condition 
information, and constantly adjusts the air/fuel 
ratio, distributor, and emissions devices for optimum 
economy, driveability, and emissions. The system 


- 83 - 


is coded 'O', '1', or '6'. This variable includes the 
entire computer system except for the oxygen sensor, 
which is coded separately (see variable #47, Form A). 

Form B - Rear 

1-4 ID Number - Same as on Form A. 

5-8 Make 

9-12 Model 

13 Vehicle Type - coded as follows: C = car, T = truck 
14-15 License Plate - State abbreviation 

16-19 Exhaust gas HC concentration (in ppm) at curb idle. 
20-22 Exhaust gas CO concentration (in percent) at curb idle. 
23-25 Odometer - mileage in thousands 

26 Dash Label - displays the fuel required and is coded 

’O' , '1' , or '7' . 

27 Catalytic Converter - oxidizes the HC and CO to water 

and CO 2 in the exhaust gas. Later model catalysts 
also reduce oxides of nitrogen. The converter is 
coded 'O', or '7' (entire catalyst canister 


removed) 



- 84 - 


28 Exhaust System - if as originally equipped an 'A' is coded. 
If non-stock a "B' is coded. 

29 Exhaust System Integrity - the condition of the exhaust 
system is coded * 1 * (no obvious leaks) or '9' (leaks 
evident). 

30 Tank Cap - seals the fuel tank during normal operating 
conditions and is coded *1*, '7', or '9' (loose cap). 

31 Tank Label - displays required fuel and is coded 'O', 

’ 1' , or '7'. 

32 Filler Neck Inlet Restrictor (unleaded vehicles only) - 
The restrictor is designed to prevent the introduction 
of leaded fuel into a vehicle requiring unleaded fuel. 

It is coded 'O', '1', '4' (widened), or '7'. 

33 Plumbtesmo - Plumbtesmo paper is used to check for the 
presence of lead in vehicle exhaust pipes. A positive 
indication is coded as 'Y' and a negative as 'Z' . 

34 Fuel Sample - indicates if inspector was able to obtain 
fuel sample for later lead analysis ('Y' or 'Z'). 


- 85 - 


2. Classification Of Component Conditions 

The table below was used to classify the various system 
components as 'tampered', 'arguably tampered', or 'malfunctioning'. 
Only those codes which are applicable to a given component 
are listed. Codes for 'not originally equipped' and 'functioning 
properly' are not included in this table. Refer to Appendix B, 

Part 1 for an explanation of the codes. 

Codes frqn form 

Ccmponent/system |2|3|4|5|6|7|8|9|B| 


Dash Label 
lank Cap 
Tank Label 

Filler Neck Restrictor 

Catalytic Converter 

Oxygen Sensor T 

PCV System 

Heated Air Intake 

Evaporative Control 
System 

Aspirated Air 

Injection System 

Air Pump Belt 


T 

T 

T T 

T A 

T T T 

T 


A 

A 

A 

T 

T 

T 

T 

A 

T 


M 


T 

M T 
M 


T M 


T M 


T = tampered 
A = arguably tampered 
M = malfunctioning 






- 86 - 


Codes from form 

Ccmponent/systera |2|3|4|5|6 |7|8 |9 |b| 


Air Pump System 


T 


T M 


EGR Gontrol Valve 


T T 


T 


EGR Sensor 


T 


T 


T 


T = tampered 
A = arguably tampered 
M = malfunctioning 





- 87 - 


3. Fuel Sample Collection and Labeling Procedures 

A fuel sample was taken from each vehicle requiring 
unleaded fuel. These samples were collected in two-ounce 
bottles with a hand-operated fuel pump. Once the sample was 
drawn, the fuel was replaced with an equivalent amount of 
unleaded fuel if the driver requested, and the pump was flushed 
with unleaded fuel. 

Each bottle was identified with an adhesive label that 
had the vehicle identifying survey number on it. The vehicle 
identifying number was the first entry on the data forms 
described in Part 1 of Appendix B. 

Prior to shipment from the field, a sample tag with the 
same identifying number was attached to each bottle. The 
bottles were packed, labeled, and shipped to NEIC Chemistry 
Branch according to the shipper's requirements and the NEIC 
Policy and Procedures Manual. 



- 88 - 


4. Plumbtesmo Application 

1) Clean a portion of the inside of the tailpipe large enough 
for the test paper by wiping it out with a paper towel or 
cloth. This may be necessary to remove soot deposits 
which might mask the color change. 

2) Moisten the Plumbtesmo paper with distilled water and 
immediately* press firmly against the surface to be tested 
for approximately thirty seconds. If the tailpipe is hot 
you may wish to clamp the test paper in the tailpipe 
using a clean clamp. 

* Note : The Plumbtesmo paper must be applied during the 

time that the paper is yellow for the reaction to take 
place. After approximately 15 seconds the yellow color 
disappears and the paper is no longer effective. Excess 
water also interferes with the reaction. 

Care must be taken to avoid contamination of the test paper. 
If a person has recently handled a test paper with a 
positive reaction, some lead or reactive chemical may 
have been transferred to their fingers. Subsequently 
handling a clean test paper may cause contamination. 

3) After removing the test paper, determine whether a color 
change has occurred. Red or pink coloration indicates 
the presence of lead. 





- 89 - 


5. Field Quality Control/Assurance 

Reference and calibration gases were used to ensure the 
accuracy of the emissions analyzer. Horiba gases certified by 
RTP were used as reference gases. Two cylinders of reference 
gas were used to validate the accuracy of the calibration gases 
before they were taken to the field on each survey. 

Three calibration gases (Horiba) were used. These gases 
were a mixture of CO and HC in nitrogen and were used to check 
the instrument at least three times daily. These calibration 
gases were certified by the manufacturer and the RTP reference 
gases. Their approximate compositions were: 

8% CO 

1560 ppm HC (Hexane equivalent) 


4% CO 

827 ppm HC (Hexane equivalent) 

1.6% CO 


320 ppm HC (Hexane equivalent) 



- 90 - 


APPENDIX C 

EMISSION OUTPOINTS FOR I/M AREAS 


The table below lists the emission outpoints used in 
the I/M areas covered in the 1985 tampering survey, 
points for pre-1975 vehicles are not included, since 
vehicles were not surveyed. 


1985 by 
The cut- 
these 


Survey Site 


Model Year 


Emissions Outpoints 
CO (% ) HC (ppm) 


New York City 

1975-77 

5.7 

700 

Metro Area 

1978 

4.3 

500 


1979 

3.0 

400 


1980 

2.7 

330 


1981 + 

1.2 

220 

Wilmington, DE 

1975-79 

— 

600 


1980 + 

— 

235 

Philadelphia, PA 

1975-79 

4.0 

400 


1980 

3.0 

300 


1981 + 

1.2 

220 

Northern Virginia 

1976-79 

4.0 

400 


1980 

2.0 

220 


1981 + 

1.2 

220 

Louisville, KY 

1975-79 

6.5 

650 


1980 

4.0 

400 


1981 + 

1 .2 

220 

Charlotte, NC 

1975-78 

5.0 

— 


1979-80 

3.0 

— 


1981 + 

1.5 

— 

New Jersey 

1975-80 

3.0 

300 


1981 + 

1.2 

220 


u 

U.S. GOVERNMENT PRINTING OFFICE: 1986-181-192/52945 


















LIBRARY OF CONGRESS 



























